¹ A preliminary note of this paper was published in The Lancet of Jan. 4th, 1902, p. 18, entitled “The Disappearance of the Addiment from Anti-Microbic Sera.” Its publication in full has been unavoidably delayed. (MS. received 4. XII. 1902. Ed.)

^{page 52 note 2} Journal of Hygiene, 1902, Vol. II. p. 85, “On the Protective Substances of Immune Sera.”Google Scholar

^{page 52 note 3} Zeitscher. f. Hygiene, 1888, Bd. IV. pp. 353—394.Google Scholar

^{page 53 note 1} The insertion of the cannula requires a little dexterity, but the method has the advantage of ensuring sterility and yielding a relatively large amount of blood.

^{page 56 note 1} The time three hours was chosen for convenience because it was found that at this period the number of colonies which grew in the control plates from ordinary bouillon had become innumerable, and therefore formed a constant standard for comparison.

^{page 60 note 1} Zeitschrift für Hygiene, 1888, IV. p. 353.Google Scholar

^{page 60 note 2} Centralblatt für Bakteriologie, 1899, V. and VI. Fortschritte der Medicin, 1892, Vol. X. pp. 9, 10.Google Scholar

^{page 60 note 3} Zeitschrift für Hygiene, 1890, VIII.Google Scholar

^{page 60 note 4} Centralblatt für Bakteriologie, 1890, VII. p. 753.Google Scholar

^{page 61 note 1} Annales de l'Institut Pasteur, 1901.

^{page 62 note 1} Münchener medicinische Wochenschrift, 1901, Vol. XLVIII. p. 679.Google Scholar

^{page 63 note 1} 2 to 4 months old for the rabbits' antityphoid sera; and about 1 year old for the horse's antityphoid serum.

^{page 66 note 1} M.L.D. = Minimal lethal dose.