^{page 73 note 1} Iberer, Münchener medizinische Wochenschrift, 06 9, 1903.

^{page 74 note 1} Handbuch der historisch-geographischen Pathologie, 1881.

^{page 74 note 2} “Report upon the Prevalence and Distribution of Hook-worm Disease in the United States.” Bulletin No. 10, Hyg. Lab. U.S. Pub. Health and Mar. Hosp. Service, 1903. The American species has only one median tooth, in place of the two dorsal teeth and four ventral hooks which surround the mouth of the A. duodenale. The bursa of the male worm is also different in the two species, and the eggs of the American worm measure, according to Stiles, about 64 to 76 μ by 36 to 40 μ instead of a mean of about 59 by 37 μ as in the case of the Old World species. Stiles adopts the names Uncinaria duodenalis and Uncinaria americana for the two worms, and calls the disease Uncinariasis or Hook-worm disease. The zoological grounds for this change of nomenclature, which is certainly very confusing, are criticised by Looss (Centralblatt f. Bakt. XXXI. p. 422, 1902). The American species has no hooks of any kind, and the disease has been generally known as ankylostomiasis or anchylostomiasis for 25 years.

^{page 74 note 3} Journ. of American Med. Assoc. Vol. XL. p. 28, 1903.CrossRefGoogle Scholar

^{page 75 note 1} Centralbl. f. Bakteriol. Vol. XXXIV. p. 533, 1903.Google Scholar

^{page 75 note 2} Centralbl. f. Bakteriol. (1) Vol. XXXIV. p. 527, 1903.Google Scholar

^{page 75 note 3} See Perroncito, Archives Italiennes de Biologie, Vol. II. p. 315 (1882) and III. p. 7.Google Scholar

^{page 77 note 1} Brit. Med. Journ. Vol. II. p. 189, 1903.Google Scholar

^{page 78 note 1} Loc. cit. p. 58.Google Scholar

^{page 78 note 2} Journal of Hygiene, Vol. III. p. 130.Google Scholar

^{page 78 note 3} Brit. Med. Journ. 1900, II. p. 541.Google Scholar

^{page 78 note 4} Treasury Dept. U.S. Hygiene Lab. Bulletin 13, 1903.Google Scholar

^{page 81 note 1} The further stages of development within the body have been investigated by Loss, Centralbl. f. Bakt. (1), 1897, p. 913. A short and copiously illustrated summary of what is known as to the structure and stages of development of Ankylostoma is given by Stiles, loc. cit.

^{page 82 note 1} Quoted by Haldane, Report to the Home Secretary on Ankylostomiasis in Westphalian Collieries, Parliamentary Paper [Cd. 1843], 1903.

^{page 82 note 2} The following data (extracted from the Greenwich Records for the fifty years 1841 to 1890) may be of interest. Mean daily temperature more than 15.5^°C. (60^°F.) on 71, and less than 4.4^°C. (40^°F.) on 56 days per annum. The mean maximum temperature is more than 15.5°C. (60^°F.) on 162 days, and more than 21^°C. (70^°F.) on 86 days, while the mean minimum is below 1.7^°C. (35^°F.) on 87 days. The average number of days per annum on which the temperature rises above 21^°C. (70^°F.) is 77, and on nearly 4 days per annum does the minimum fail to fall below 15.5°C. (60^°F.). The average number of days on which the temperature falls below freezing-point is 56, on nearly 5 of which it remains continually below 0^° for 24 hours.

These figures must not be applied too closely to the Ankylostoma problem. Other factors have to be taken into consideration, such as exposure to direct sunshine in sheltered places such as quarries, cooling of the faecal mass by evaporation, &c. If, as appears to be the case, small variations of temperature about 16^°C. are important, different parts of England must be considered separately. The mean annual temperature at Greenwich for the years 1841—1890 was 9.7°C. (49.46^°F.), while that of Penzance is 11.5^°C. (52^°F.). These figures are misleading in the sense that they tell us nothing of the prevalence of hot spells in the summer and of spells of cold in the winter of sufficient severity to kill Ankylostoma eggs and larvae.

^{page 83 note 1} See Haldane, loc. cit.

^{page 84 note 1} This has never, so far as we are aware, been definitely shown for Ankylostoma, but a chitinous coating is certainly present in most Nematodes.

^{page 84 note 2} Arch. Ital. de Biol. III. 1882, p. 7.Google Scholar

^{page 84 note 3} Bull. Acad. Roy. de Médecine de Belgique (4) XV. 1901, p. 397.Google Scholar

^{page 85 note 1} This is true of course only with some dry system of dealing with faeces. With a water-borne system there is no danger from infected stools except possibly on sewage farms. In some places underground it is true that the water will wash any disinfectant away from the faeces: but under such circumstances the abundance of water will of itself be a great hindrance to the development of the eggs.

^{page 87 note 1} Haldane, loc. cit. p. 5.Google Scholar

^{page 87 note 2} Centralbl. f. klin. Med. 1886, p. 675.Google Scholar

^{page 87 note 3} Centralbl. f. Bakteriol. Vol. 34, p. 533, 1903.Google Scholar

^{page 87 note 4} Centralbl. f. Bakteriol. Vol. 24, p. 486, 1898;Google ScholarCentralbl. f. Bakteriol. Vol. 29, p. 733, 1901.Google Scholar

^{page 88 note 1} Arch. Italiennes de Biologie, Vol. 37, p. 269, 1902.Google Scholar

^{page 88 note 2} Brit. Med. Journ. 1902, Vol. 1, p. 190.CrossRefGoogle Scholar

^{page 89 note 1} Centralbl. f. Bakt. Vol. 33, p. 338, 1903.Google Scholar

^{page 90 note 1} In one of the animals there were some small haemorrhages in the mucous membrane, and in the other no haemorrhages. The young worms contained no blood. As, however, the signs of anaemia seem to have been very marked this experiment seems to confirm the conclusion which we put forward in our previous paper that the anaemia cannot be explained by loss of blood caused by the bites of the worms.

^{page 90 note 2} Arch. Italiennes de Biologie, Vol. 37, p. 271, 1902.Google Scholar

^{page 91 note 1} Thompson-Yates Laboratory Reports, Liverpool, 1902, p. 471.Google Scholar

^{page 94 note 1} See the table in B. Scheube (Diseases of Warm Countries, Eng. Trans. 1903, p. 420). The extremes given here are: length 44 to 70, breadth 23 to 43. Our own measurements give 56 to 70 × 37 to 50, with an average of 62 × 42 μ. According to C. W. Stiles (Treasury Dept. U.S. Hygienic Lab. Bull. 10, 1903) the eggs of the American species (Uncinaria americana) are a good deal longer (64 to 76 μ × 36 to 40 μ).

^{page 94 note 2} Medical News, Vol. 82, 1903, p. 682.Google Scholar

^{page 94 note 3} Report on Kála-Azár, Shillong 1890, p. 109.Google Scholar

^{page 94 note 4} loc. cit.

^{page 95 note 1} The American species differs in some particulars: vide supra p. 74.Google Scholar

^{page 96 note 1} We are assuming that the larvae found bear some superficial resemblance to those of Ankylostoma. Dipterous and coleopterous larvae can and do occur in these faecal deposits; they are easily separated by their segmentation, the presence of hairs, eyes, the elaborate mouth, &c. Unless the worm is unsegmented it cannot be a Nematode.

^{page 97 note 1} Some samples collected in a Shropshire mine by Mr John Cadman, H.M. Inspector of Mines (who kindly sent them to us for examination), were full of some Nematode belonging to the family Anguillulidae. The eggs were very similar to those of Ankylostoma, but were rather smaller (41 to 60 × 28 to 34; average 53 × 32 μ), the sides were somewhat flattened by pressure within the mother's body, the contents filled the shell more completely; and the young larvae which were present in some of them were larger. Similar eggs were to be seen within the bodies of the adult females which were present. There is every reason for supposing that these were free-living Nematodes which had entered the faeces subsequent to their deposition in the mine. The larvae which were present showed that they were not Anguillula.

^{page 98 note 1} Good summaries of our knowledge of the life-history of this worm are given by W. S. Thayer (Journ. Exp. Med. VI. 1901, p. 75), and R. P. Strong (Johus Hopkins Hosp. Reports, X. 1902, p. 94). Strong's case had 0.1 to 0.3 p.c. eosinophiles but had some leucocytosis from an abscess at the time.

^{page 98 note 2} München. med. Wochenschr. 1894, p. 22.Google Scholar

^{page 98 note 3} Boston Med. and Surg. Journ. CXLVIII. 1903, p. 583.Google Scholar

^{page 98 note 4} Centralbl. für Bakteriol. XXVI. 1899, p. 608.Google Scholar

^{page 99 note 1} Volkmann's Sammlung klinischer Vorträge, No. 265, 1885, p. 2478.Google Scholar

^{page 101 note 1} Stiles, loc. cit. p. 87.Google Scholar

^{page 102 note 1} Lancet, 1894, I. p. 1365.Google Scholar

^{page 102 note 2} Brit. Med. Journ. 1900, II. p. 541.Google Scholar

^{page 102 note 3} American Journ. Med. Sciences, CXXIII. 1902, p. 28.Google Scholar

^{page 102 note 4} loc. cit.

^{page 105 note 1} For recent detailed information with regard to the Westphalian outbreak see the Report by Dr Haldane to the Home Secretary on Ankylostomiasis in Westphalian Mines, Parliamentary Paper [Cd. 1843], 1903: also special supplement to the Colliery Guardian, November, 1903.

^{page 108 note 1} Barbier. Paper read before the International Congress of Hygiene, Brussels, 1903, Section IV. The figures are given in the Table at the end of the paper.