David Becher and the networks of Enlightenment medicine

Unlike those contemporary ‘local experts’ of spa waters who were in fact erudite amateurs, Becher's plans to produce a medical salt from the springs in his home town drew nourishment directly from the heart of the Habsburg scientific world, which he had frequented during his years of study and training at the most important sites of the empire's intellectual life.Footnote ¹⁰ In 1744, when he was nineteen, Becher had left Carlsbad to go to Prague, the Bohemian capital, where he acquired the fundamentals of natural science at the university, the oldest in central Europe.Footnote ¹¹ Chemistry, which through the ‘iatrochemical’ trends had acquired a high standing in the disciplinary canon of medicine in the first half of the eighteenth century, quickly became his special area. Nonetheless, after taking his doctorate, Becher refused the offer of a chair of chemistry at the university's medical school. Instead, in 1751 he moved from Prague to the imperial capital, in order to complete his training at the Vienna Hospital, the stronghold of Enlightenment medicine in the Habsburg Empire. The hospital, organized by the empress's personal physician, Gerard van Swieten, on the model of the Leiden hospital, not only had an outstanding reputation because of its proximity to the imperial court, but with its accent on training physicians at the patient's bedside it also exercised an immense intellectual influence on the developments of contemporary medicine, which Michel Foucault and other historians of medicine have vividly described.Footnote ¹²

Although Becher thus came into contact with the latest scientific methods in both intellectual centres of the empire, in 1758 he resigned from his position at the Vienna Hospital in order to set up as a spa physician in his birthplace, Carlsbad, far away from both the capitals. At this time, Carlsbad was situated at the western margins of the empire and was heavily affected by the conflicts between the Habsburg and Prussian armies of the Seven Years War and the military events in nearby Saxony. From a modern point of view, it thus may seem hard to understand why Becher moved to Carlsbad. However, this move contradicted neither his scientific ambitions nor the outlook for making the rest of his life secure. In actuality, practising medicine in what was then one of the best-known spas in the Habsburg Empire promised to provide a substantial income and social prestige, because sojourning in Carlsbad and pursuing a cure there by drinking its mineral water was one of the typical summer activities of the Bohemian nobility and the country's prosperous burgers, who traditionally spent the months preceding hunting season in one of the spas in the Bohemian spa triangle.Footnote ¹³ In addition to visitors from the Habsburg territories there were always also guests from neighbouring Saxony and the nearby dukedoms of central Germany, some of which were geographically much closer to Carlsbad than was Vienna (which was about 340 kilometres away). The numerous and extended cures regularly undertaken in Carlsbad by Johann Wolfgang von Goethe and other prominent contemporaries prove the attraction of the Bohemian spa to the Enlightened elite of these central German regions.Footnote ¹⁴

However, in addition to the spa physicians who settled there, in the eighteenth century there were also many practitioners of other, more artisanal healing professions in Carlsbad and other central European spas. In accord with the contemporary order of knowledge, barber–surgeons and other ‘quacks' were responsible for the care of all external diseases and thus also of many of the spa's guests. These practitioners were not perceived by Becher as serious competitors, since social elites considered consultation with an academically trained physician to be the treatment appropriate to their standing.Footnote ¹⁵ Moreover, in developing his ‘business contacts’, Becher was aided by his connections with the medical school in Vienna, whose professors advised members of the high nobility living at the court to consult colleagues known to them.Footnote ¹⁶ Thus he treated, among others, the chancellor of the Bohemian government, Count Chotek, when he was taking a cure in Carlsbad – a circumstance that later turned out to be an important advantage for the physician in the controversy over the production of Carlsbad salt.Footnote ¹⁷

From a scientific point of view, beginning a practice as a spa physician in the middle of the eighteenth century was in no way tantamount to withdrawing from the Enlightened scientific community. In accord with the decentralized structure of the République des lettres, which manifested itself not only in the academies and universities in the capital cities but also in an extended network of scientific correspondence and publications,Footnote ¹⁸ Becher was able to take part in the academic debates of his time from his home town. This is shown, for instance, by his Neue Abhandlung vom Carlsbad (A New Treatise on Carlsbad), a respected scientific study on his home town's mineral springs, and the publication of an article in a respectable scientific journal that was edited by the masonic lodge of Prague.Footnote ¹⁹

The structure and development of his book, which was published at Becher's own expense, reveal the points on which his scientific reputation was based: as a ‘chemical and physical investigation of the Carlsbad hot springs’, his study was in its subject and its methods in complete accord with the system of a chemical–medical investigation of mineral springs developed around 1700 by Friedrich Hoffmann, a highly reputed professor of medicine at the University of Halle.Footnote ²⁰ Scientific works modelled on Hoffmann's method were published in increasing numbers during the eighteenth century on almost every spa of the Holy Roman Empire, making spa medicine one of the main fields of expertise in German Enlightened medicine.Footnote ²¹ All authors, generally the local physicians, sought to demonstrate the curative effects of ‘their’ spring water by means of a detailed chemical analysis and a precise description of its medical effects on the patients.Footnote ²² The often rather short treatises thus served in some ways as a form of advertising for the different spas by spreading the news of their curative power to a wider Enlightened audience.

In accord with Hoffmann's scheme, in his treatise Becher first discussed the ‘natural history of the Carlsbad hot springs’ and then described in detail the various steps in the chemical analysis of its spring water.Footnote ²³ He referred extensively to the ‘hydrothermometer’ used in the tests, in order to demonstrate the familiarity with the latest instruments that was necessary to uphold his reputation as a scientist.Footnote ²⁴ However, Becher had been obliged to acquire the practical chemical skills for this analysis – at least he acknowledges in the preface to his book that he received crucial advice about his investigation through his correspondence with Dr Troschl, a very experienced chemist from Prague.Footnote ²⁵ This kind of recourse to the practical knowledge of a colleague was, however, not unusual, since many natural scientists of the time found it quite normal to base their publications on tests that were carried out not by themselves but by their assistants.Footnote ²⁶

This wide-ranging intellectual network from which Becher drew his scientific knowledge was of crucial help to him in getting Habsburg officials to accept his recommendations for producing Carlsbad salt. Because they themselves lacked the necessary scientific competence, in investigating his proposal these officials had to rely on the chemical expertise of other physicians who were active in the milieu of the imperial court in Vienna and in the medical administration. For example, in a letter of recommendation written in French in 1770, the court physician Van Swieten confirmed Becher's scientific reputation, which the latter had acquired through his studies on the local mineral springs and especially on the carbonic acid their water contained – a central problem in contemporary chemistry:

The formulation chosen by Van Swieten is exceptionally informative, because it refused an explicit judgement on the author's theses regarding the origin of the carbonic acid. His positive assessment of Becher's work refers solely to the precise fulfilment of the conventions that were generally required for the analysis and description of a mineral spring: the physician's reputation as an Enlightened scientist in the eyes of the contemporary scientific community is based not on his talent for scientific discovery, but first of all on his familiarity with the established practices of producing and validating knowledge in the natural sciences.

The Habsburg administration's knowledge cultures

For the Enlightened Carlsbad physician, the intellectual centres of central and eastern Europe – the university cities of Prague, Vienna, Halle and Leiden and their academic institutions – represented the essential reference points of his own order of knowledge. The officials entrusted with the case drew their visions from another intellectual and social background: the world of the imperial court in Vienna and the Habsburg administration, which in those years was being comprehensively reformed under the authoritative influence of Joseph von Sonnenfels in accord with the principles of Enlightenment doctrines of public policy and cameralism.Footnote ²⁸ For Becher, this meant that in his circle he had to base his strategy of persuasion from the outset less on his scientific reputation and knowledge of chemistry than on the integration of his argumentation into contemporary administrative discourse.

Becher's most important point in his 1763 proposal to produce a laxative salt was thus the reference to the great savings in expensive firewood that would result from using the method of evaporation he had developed. This was based essentially on the construction of special vessels that used the spring's own warmth to evaporate the water: they floated on the warm waters of the spring pond and absorbed its heat, which then evaporated the water inside. In his letter to the Prague regional government, Becher therefore goes on at great length about the possibility of ‘preparing the salt without wood’: in fact, the ‘hot spring’ can in this way ‘be used instead of wood’.Footnote ²⁹ With such arguments, Becher entered entirely into the cameralist discourse of the contemporary administration, which in general urged frugal use of natural resources and especially regarded the allegedly rampant ‘shortage of forest’ as a basic problem for the economic foundations of the state.Footnote ³⁰ And in fact imperial officials proved to be very open to this justification: the Bohemian chancellor, Count Chotek, to whom Becher had personally presented his plans while Chotek was taking a cure in Carlsbad, asked him to submit a detailed report on the new production method as soon as possible.Footnote ³¹

However, Becher's scientific justification played only a minor role in the emperor's subsequent approval of his application on 25 February 1764. Becher's economic arguments, according to which the salt could be produced very economically using the method he recommended, seem to have been far more important. In his presentation for the imperial court chancellery, Count Chotek emphasized the potential savings in expensive firewood and pointed out that the method would serve the ‘best interests of the city’.Footnote ³² Dr Mitterbacher, a physician who was responsible for medical administration in the Elbogen administrative district, had also praised Becher's novel method of salt production as a procedure that was especially advantageous economically.Footnote ³³

As is shown by the subsequent course of events, when the decline in the number of summer spa visitors at the end of the 1760s was eliciting ever greater unease among the local population and had in the meantime led to a cessation of the medical salt production, officials and members of the court in Vienna lacked the knowledge required to understand Becher's chemical and technical arguments. This is made clear, for example, by the express request made by the regional government to the dean of the Prague medical school for a translation of the expertise written in French by the Dutchman Van Swieten; because of its technical vocabulary, government officials were unable to translate it into correct German.Footnote ³⁴ Before allowing Becher's production of his purgative salt to continue, the empress wanted assurance from various ‘native and foreign physicians’ that ‘the salt made from Carlsbad mineral water does not have the same effect as Carlsbad water itself, and thus can be sold without any disadvantage to the latter’.Footnote ³⁵ Thus officials were not able themselves to understand Becher's scientific arguments concerning the composition of the salt he produced, so that these had first to be validated by other experts trained in chemistry. However, since these Enlightenment physicians shared Becher's knowledge culture, both his scientific reputation and his network tipped the scales in his favour, and it was relatively easy for him to win the renewed support of officials and the court for his project.

Becher's first victory did not entail, however, the disappearance of all resistance on the local level, where there had been opposition to his enterprise from the beginning. This resistance came, for instance, from Josepha Müller, the widow of a local pharmacist, whose deceased husband had earlier carried on a relatively lucrative production of medical salt for local use. Although she never challenged Becher's vision of the laxative salt, she raised a series of objections against the imperial privilege granted Becher in order to get at least some compensation for her lost income. Her attacks were unsuccessful, however, because after Becher transferred production to the city administration in 1767 and withdrew into an uncontroversial role as an expert adviser, the widow's argument that the privilege was an unjustified financial advantage lost its foundation.

Far more problematic for Becher were the massive objections made by the city's residents, which led in the spring of 1767 to violent protests against the physician and the manufacturing facilities he had built. In May the conflicts escalated so far that the government in Prague was obliged to intervene. To the great ‘annoyance of their guests at the spa’, the Bohemian chancellor Count Chotek wrote in a letter to the responsible district captain, the ‘ferment and turmoil’ prevailing among the residents of Carlsbad had disrupted production of the medical salt.Footnote ³⁶ He demanded a thorough investigation of these events and threatened to send in the army to restore order in the city. Although the Carlsbad magistrate vehemently defended himself against Becher's claim that there was a ‘conspiracy’ against him and that he had been personally slandered, the district captain's subsequent official investigation was not able to clarify what had happened. At the ad hoc meeting held in the city, however, the residents expressed their massive objections to the production and sale of the salt, which was once more blamed for the decline in the number of visitors to the spa.Footnote ³⁷

Becher regarded the obligation to demonstrate his expertise before the city's residents, and thus before laymen, as an affront to his professional honour, to the point that he added to the district captain’s record of the debate a written elaboration in which he once again set forth in detail his arguments for distinguishing between the medical salt and the effects of the spring water.Footnote ³⁸ In this statement he complained at length about the disrespect for his professional competence and lamented that ‘I had to discuss a medical subject before a bunch of artisans and as it were subject myself to their judgement’.Footnote ³⁹ Becher's refusal to give a public explanation and demonstration of his expertise is exceptionally noteworthy, because in this he clearly differed from other natural scientists of the Enlightenment, who definitely did present their scientific knowledge to the general public.Footnote ⁴⁰ In this connection, Jan Golinski has even called eighteenth-century British chemistry ‘science as public culture’.Footnote ⁴¹ In contrast, the statement Becher wrote after the fact, and thus did not read at the public meeting, emphasizes the symbolic boundary line he sought to draw between his own expert academic knowledge and the ‘lay’ audience he scorned.Footnote ⁴² He considered the only legitimate audience for his scientific knowledge to be the Enlightened public that in his view consisted of the medical scientific community and the state authorities.

In this way, the written nature of his position statement clearly distinguished Becher from the oral knowledge culture of the public discussion. This may still reveal a reflex of the older view of science as a ‘hermetic’ form of knowledge accessible only to initiates and the powerful.Footnote ⁴³ Above all, however, Becher's statement gave him an opportunity to make his voice as an expert even more clearly heard in the bureaucratic decision-making process. In his statement, he was obviously seeking to achieve a simple, non-technical mode of presentation in repeating the arguments he had already emphasized in his first letter to the Prague government.

But this time, as well, it was ultimately not the grounds laboriously laid out by Becher that led the Habsburg authorities to allow the production of his laxative salt to continue. Instead, government officials in Prague – as they emphasized in their presentation before the empress – saw ‘nothing new’ in Becher's discussion of the chemical composition and medical effects of the salt.Footnote ⁴⁴ The only thing that impressed them was the data collected by the authorities regarding the numbers of guests at the spa over the past nine years. In their view, these data provided sufficient arguments for the continuation of the salt production, since in their view the observable fluctuations in the number of visitors that had aroused the residents’ fears could be explained ‘rationally’ as a response to military events and the difficult economic situation. Against the background of what they considered the unclarified question regarding the nature of the salt produced and its medical effectiveness, the authorities therefore argued, in good cameralist fashion, that ‘in the best interests of the city’ and for economic reasons, the continued production of the salt ‘at such low cost’ should be recommended.Footnote ⁴⁵ Given these circumstances, the empress not only decided to continue production without regard to the resistance in Carlsbad, but also ordered that in the future only a ‘decision at the highest level’ – that is, an official imperial ruling – could record any decline in the number of guests.

Given their knowledge culture dominated by political and economic considerations, it is hardly surprising that the authorities nonetheless continued to take seriously the fears of Carlsbad residents that the sale of the medical salt might significantly decrease both local businessmen's income and the numbers of foreign guests at the spa. The lively correspondence among the court in Vienna, the castle in Prague and the district captain between 1770 and 1772 demonstrates officials’ efforts to calm the people's fears. The investigation brought to light the fact that ‘it is well known that Carlsbad salt is openly sold in pharmacies in Vienna and everywhere else’, although the salt was not delivered by Becher directly.Footnote ⁴⁶ Especially since in many places the salt was sold at a lower price than in Carlsbad, the authorities decided that this must be another salt that was being sold under a false name. Resourceful pharmacists were obviously using the name of the famous spa with intent to deceive, especially since the external appearance of the product did not allow laymen clearly to distinguish it from other laxative salts.

Under these circumstances, in order to allow customers to be sure that they were buying the real thing, in June 1772 the imperial court in Vienna ordered that henceforth only ‘salt in one-half and one-pound packages bearing the seal of the city of Carlsbad and the words “Carls baader Saltz” … may be considered genuine Carlsbad salt’.Footnote ⁴⁷ This official decision was not unusual in the embattled market for specialized pharmaceutical products in the eighteenth century, since other ‘secret remedies’ and medicines also had such privileges and were sold with a special seal of approval and their own packaging.Footnote ⁴⁸ Nonetheless, the regulation ultimately contradicted the view defended by Becher and his colleagues that Carlsbad salt was basically chemically identical with other purgative salts. Putting the city's seal on the packaging introduced a new symbolic distinction that for consumers closely connected the salt with the fame of the spa and its mineral springs. Thus the decision absolutely took into consideration the residents’ objections, which had always emphasized the special nature of the medical salt's healing effects and its identification with the local mineral springs.

From the Carlsbad magistrates’ point of view, the regulation represented a very acceptable compromise, whose acceptability was tested ten years later when Becher's method of producing the medical salt once again encountered public criticism. The trigger was a letter from the dean of the Prague medical school, Mikan, who in a petition to the Prague government pointed out crucial defects in Becher's method in relation to the purity of the product.Footnote ⁴⁹ In contrast to the earlier petitions submitted by Carlsbad residents, the Prague professor first put Becher's reputation in the scientific community into question. Becher had to admit that the production of the salt using the evaporation method he had introduced, and which he had always described as easy to carry out, raised significant problems in its practical application.Footnote ⁵⁰ According to Becher, however, the reason for this was not fundamental errors in its construction, but rather faulty manipulations by the workers involved.Footnote ⁵¹ In addition, he said, such fluctuations in the consistency of the mineral salt produced should be described as ‘normal,’ and ‘not a reason for concern’ on the part of prescribing physicians. Therefore Becher dismissed the idea of a product of unified and standardized consistency set forth in the report signed by two of his colleagues and the local pharmacist – thus clearly contradicting the conception he had always previously defended and also the widespread public image of the Carlsbad salt brand.

Becher's faltering scientific reputation caused the imperial authorities to request further expert evaluations in order to restore their confidence that his method was well founded. But like the dean in Prague, who in his official report formulated his earlier objections much more reservedly and asked chiefly for greater care in producing the salt,Footnote ⁵² the head of the state medical administration, Proto-Medicus Freiherr von Störk, ultimately supported Becher's position.Footnote ⁵³ Against this background, Emperor Joseph II decided, despite all the resistance in the city, to continue the sale of the medical salt outside Carlsbad, since a ‘prohibition on the free sale of the salt [would] inevitably result in the loss of the previous inflow of money, to the most painful disadvantage of the city’.Footnote ⁵⁴

The circulation of ‘local knowledge’

Whereas the Prague government's records make it relatively easy to reconstruct the networks used by the imperial authorities and by science in the controversies over Carlsbad salt, we find only a few clues to the contexts of communication in which the local knowledge of the residents of Carlsbad circulated. Reports and petitions from the residents are lacking in our documentation, so that no direct analysis of their arguments on this topic is possible. However, the report submitted by the district captain after the public meeting in the city in May 1767 provides at least a certain insight into the social world from which the objections to Becher's project sprang. For his part, Becher had blamed first of all ‘landlords and especially the city's artisans who hawk their wares door-to-door’,Footnote ⁵⁵ thus making responsible two groups that were in special ways in contact with the outside world: on the one hand, homeowners and innkeepers who put their houses at the disposal of foreign guests during the spa season (this group of inhabitants must have felt they were most strongly affected by the decline in the number of visitors, since they profited directly from the income produced by spa tourism); on the other hand, travelling hawkers who went about the region with their wares and had a particularly important function in providing the local population with a means of exchanging information.

Three persons expressed themselves personally before the district captain, and also openly discussed the motives that underlay their sceptical attitude towards the salt production. All three – including a municipal judge whose appearance as one of Becher's opponents points to the social bandwidth of the local resistance to the production of the salt – referred to statements made by third parties whom they cited as guarantees of the credibility of their views. For example, the ‘Carlsbad Professions Wares’ dealer, the hawker Matthes Raab, explained that on his travels in the Frankish-central German area he had ‘heard it said in all these places that Dr. Becher had made people happy everywhere through the public sale of his salt, because they could save the money that would otherwise be paid for the later trip to Carlsbaadt [sic].’Footnote ⁵⁶ According to the district captain's report, Raab mentioned by name the cities of Nürnberg, Würzburg, Coburg, Hilburghausen, Meiningen, Sachsen, Gotha, Weimar, Sondershausen and Bayreuth – all cities to the west of Carlsbad, outside the Habsburg Empire, that had been engaged since medieval times in a lively regional trade with the eastern Bohemian cities. For his part, the municipal judge Struntz reported on a letter from a Polish aristocrat, Baroness Dieschinin von Tuchowitz, who had ordered two and a half pounds of medical salt to use for curative purposes outside the city. Finally, the ‘Burger’ Johann Joseph Weißhaupt referred to the statement of a physician from Pilsen who had issued a warning:

The relatively high social status of their consultants and the expertise of the physician from Pilsen made these statements seem to city's residents particularly trustworthy, and must have made them even more suspicious of Becher's claims. In view of what seemed to them to be contradictory opinions, Becher's expert knowledge must have seemed all the more doubtful the greater their fear regarding the possible economic damages they might suffer as a result of the predicted decline in the number of spa visitors.

In comparison with the scientific networks Becher could draw on to validate his views and the authorities consulted by the Habsburg administration in its investigation of the case, the regional distribution of the referees named by Becher's three opponents reflects a different geography of knowledge. The manifold interwoven relationships that bound the residents of the city to their environment also represented spaces of validation and circulation of ideas regarding the Carlsbad salt that were considered by those concerned as proven ‘knowledge’ about its properties. Even if the combination of the individual referees was certainly aleatory in many respects, the person and places pointed clearly to three different spheres in which information and goods circulated in and around the city: first, the elementary trade contacts that bound western Bohemia much more strongly to the central German area than to the Habsburg heartland around Vienna; second, the bonds of friendship that were formed between residents and members of the central European aristocracy and bourgeoisie as a result of the latter's visits to the spa; and third, the ‘normal’ regional relationships between Carlsbad and Pilsen, the provincial capital of the neighbouring district.

But Carlsbad residents’ knowledge was constructed not only on the opinions of their outside warrantors. It also relied on their own practical experiences with the local mineral water, whose special curative effects had been demonstrated by the many generations of sick people who had sought treatment at the spa. Since in many respects this water was the source of their income, the burgers obviously did everything they could to protect it against outside exploitation. Their daily experience with the spring gave them very concrete knowledge about its nature, and this knowledge made them extremely suspicious about the physician's statements regarding the production of a uniform and stable ‘salt’ that was said to be contained in the water but whose effects and composition should be differentiated from it. Even more improbable seemed to them the idea that this product would not differ in its composition and medical use from those salts made from the water of other spas. Part of what they knew from their own experience was that the spring's intensity could fluctuate considerably. New springs repeatedly appeared at the most diverse places in the city, and their emergence was often connected with a decrease in the main spring's flow. However, the residents considered water from the main spring to be especially curative, so that they greeted with mistrust every new spring that broke forth.Footnote ⁵⁸ In view of several generations’ positive experience of the old spring's healing power, caution with regard to new springs, with their still unknown composition, was entirely sensible, even if in his description of such a new spring Becher commented on this attitude with a certain amazement.Footnote ⁵⁹ Against this background, the gradually decreasing overall output of the main spring, which Becher also noted,Footnote ⁶⁰ aroused special concern among the city's residents. This concern could not be dissipated by arguing that the total quantity of water in the Teplá River was generally not affected by such phenomena.Footnote ⁶¹ So long as this did not affect the main spring located within the city, residents regarded such arguments as irrelevant.

The devices used to evaporate the spring water, especially the kettle floating in the spring water, aroused similar fears, since it was thought that they too could hinder the flow of spring water and cause the ‘depressed’ water to break out elsewhere. Had such an outbreak occurred beyond the city limits, so that the new spring lay outside their direct control, it would have decreased their earning power. Becher rejected this kind of concern by referring, on the one hand, to the natural qualities of the environment, which in his view precluded the emergence of a new spring outside the city, and on the other hand, to the possibility of sealing up any such outbreaks. But the residents’ fears could not be entirely dispelled. Moreover, their concern was fed when the installation of a heavy copper container Becher had had made for producing the salt caused a smaller outbreak of the mineral water, which was patched over merely with wood.Footnote ⁶²

In addition to the spring's fluctuating intensity, the residents also noted its sometimes decreasing mineral content, which they detected in their daily use of the spring water by changes in its smell and taste. In 1766, Becher also observed that ‘the spring water has seemed to me and to many visitors to be somewhat saltier on some days than on others’.Footnote ⁶³ Hence careful observation of the spring was important, especially since the changing composition of the water also had to affect the course of the medical cures. The experiential knowledge gathered in this way also raised the status of the local population in the eyes of incoming patients, because only on site was continuous observation of the water over a long period of time possible. Carlsbad residents therefore also had, as Becher acknowledged, a great influence on visitors to the spa, even when it was a matter of assessing new springs.Footnote ⁶⁴

Given their strongly rooted knowledge of the healing power of ‘their’ spring and its variable quality, the residents reacted in an accordingly helpless way to the diverse views expressed by Becher on the one hand and on the other by those ‘experts’ they themselves had consulted regarding the nature of the salt produced from it. The statement made by the physician, ‘that the salt is not specific … and may be harmful’,Footnote ⁶⁵ seemed to contradict completely the local experience confirmed by several generations about the distinctive effects of internal cleansing caused by the Carlsbad spring water and thus its abilty to generally strengthen the health of the patients.Footnote ⁶⁶

But not only did Carlsbad residents’ lack of understanding of the physicians’ chemical argument crystallize against the background of their practical knowledge about the spring water. In fact, their vision was also secured by those outside experts who claimed that the curative effect of the mineral water was ‘identical’ with that of the ‘salt’ produced from it – a vision that circulated not only among the different ‘witnesses’ cited but also among those contemporary doctors continuing to prescribe the salt to their patients in order to spare them the costly trip to the spa city.Footnote ⁶⁷ The contradictory visions of contemporary doctors thus added another motive for the ‘completely unfounded’ practice of patients, who ‘use it for two, three, or several days as a springtime cure, or a mild laxative’.Footnote ⁶⁸

If we try, unlike Becher and the other physicians involved in the mineral water controversy, to fathom the rationale lying behind these convictions about the ‘Carlsbad salt’, we must refer first of all to the older, originally alchemically shaped conception of the nature of a salt. According to alchemical doctrine, a salt was the solid material that remained after a process of evaporation through distillation.Footnote ⁶⁹ In the alchemists’ Neoplatonic conception, a salt was an ‘essence’, the general material basis for life and for inanimate nature, and could in principle be obtained from any material.Footnote ⁷⁰ In its choice of words, Becher's resigned conclusion, ‘that many external [patients] who have no conception of the nature of the springs here, very mistakenly regard this salt as the essence and extract of the local water’,Footnote ⁷¹ points to the fact these originally alchemical views were shared by both inhabitants and external patients who, against the advice of Becher and other doctors, took the salt in order to avoid the journey to the spa city.

In fact, the vision of a general identity of the salt and the spring had been encouraged a generation earlier by Friedrich Hoffmann (1660–1742), who as professor of medicine in Halle and well-known authority on the medical use of spas could not be suspected of harbouring ‘alchemical’ views. Hoffmann's 1734 published brochure on the Carlsbad salt (which, at that time, was only produced and sold by the local pharmacist) points, by its unclear use of the concept of ‘salt’ in certain passages,Footnote ⁷² to the old notion of ‘essence,’ as for example when the author characterizes mineral salts in general by saying that they would ‘communicate their curative power to mineral springs’.Footnote ⁷³ Unlike Becher and the physicians of the late eighteenth century, Hoffman was convinced that ‘natural’ salts from mineral springs ‘consist of far more delicate and subtle principles than the alcalia also prepared as media salia’.Footnote ⁷⁴ But above all, in his work he expressly praises the special effect of Carlsbad salt, which was ‘far more delicate and subtle’ than the salt obtained from the Sedlitz curative water.Footnote ⁷⁵ In this sense, Hoffmann can be seen as a transitional figure who – against the background of a chemical science that had already progressed further – still disseminated the older alchemical view of the salt obtained, a view to which some Carlsbad residents, and also many patients, still held a generation later. Therefore, even if Becher's contemporaries did not necessarily share the philosophical implications of the classical alchemical ideas, the concept of essence in itself was still very much alive among them, especially as it seemed to be confirmed by the practical experience of Carlsbad's inhabitants and the viewpoints expressed by their outside warrantors. This conception of an identity between mineral water and medical salt was also involuntarily encouraged by the special packaging introduced by Habsburg officials, because the latter emphasized the close relationship between the city and the medicine sold.