¹ Including one from a neighbouring village, and excluding four cases in which symptoms of diphtheria were absent or uncertain and which were notified because suspicious bacilli—which were afterwards recognised as Hofmann's bacilli—had been found.

¹ The pseudo-diphtheria bacillus first described by Löffler, and afterwards by Hofmann and others, is called throughout this paper by the name of Hofmann, in order to clearly distinguish it from the true diphtheria bacillus with which the name of Löffler is usually associated.

² Roux, and Yersin, (Ann. de l'Inst. Pasteur, 1890, vol. iv. p. 385)Google Scholar, ten years ago expressed the opinion that the frequent presence of the pseudo-diphtheria bacillus in the mouths of healthy persons and others not suffering from diphtheria, does not interfere with the bacteriological search for the true bacillus. They arrived at this opinion because of the small number of colonies of the “pseudo-” bacillus when present. It is doubtless true as a rule that the colonies of this micro-organism are not numerous. But I have several times found cultures from the nose and pharynx consisting of very numerous colonies almost all of which were made by the bacillus of Hofmann, and on the other hand from cases of diphtheria both active and convalescent I have had cultures with only one or two colonies of diphtheria bacilli. Roux and Yersin stated that their pseudo-bacilli produced acid, but their description would seem to include the Hofmann bacillus. They wrote before the importance of the acid test had been recognised, and it is probable from the frequency with which they found their pseudo-diphtheria bacilli (in 40 per cent. of the children of a school in a healthy country village) that their group of pseudo-diphtheria bacilli included both the attenuated diphtheria bacillus and the bacillus of Hofmann.

¹ First suggested by Prof. Lorrain Smith of Belfast. For the preparation of this nutrient medium see Brit. Med. Journ. 1894, vol. ii. p. 1177.Google Scholar

² Experience gained during this investigation confirmed the generally accepted opinion that antiseptics applied to the throat not unfrequently render the bacteriological examination useless or misleading. Practitioners can scarcely be reminded too often of this fact.

¹ Trans. of the Assoc. of American Physicians, 1900.Google Scholar

¹ It is true that 8 out of 83 animals injected died within 10 days of inoculation, but that they did not die from the bacillus in question is clearly shown by the following considerations, (a) there was no oedema at the seat of inoculation in any during life, (b) nor after death, and there was no excess of pleural fluid, (c) the injections were in all cases repeated, sometimes in larger doses, and the animals remained well, (d) though the 83 injections occupied two months and more, all deaths happened during one week, and were probably therefore due to some cause other than the injection.

² In these four instances it seemed probable that the bacilli first seen and classed under A were true diphtheria bacilli, and that the attempt to isolate them failed and resulted in isolating a pseudo-diphtheria bacillus instead.

¹ Among over 5000 suspected cases of diphtheria in New York Park and Beebe found the diphtheria bacillus in about 60%. Morse found it in 72% of 301 cases of diphtheria in the Boston City hospital. (Cited by Welch, , “Bacteriological Investigation of Diphtheria in the United States,” Am. Journ. of Med. Sci. 10 1894.)CrossRefGoogle Scholar

¹ Roux and Yersin have made a similar observation.

¹ During the past six years I have met with other bacilli which more or less resemble the diphtheria bacillus. These mostly came from the skin. The above-mentioned types are the only diphtheroid forms which I have found in the nose or pharynx.

² New York Med. Rec. xlvi. 1894, p. 385.Google Scholar

¹ Trans. Brit. Inst. Prev. Med. first series, p. 7, 1897.Google Scholar

² Guy's Hospital Reports, vol. liii. p. 55, 1898.Google Scholar

¹ Trans. Jenner. Inst. Prev. Med. Second Series, p. 113, 1899.Google Scholar

¹ See paper by Hill, H. W., M.D., Journ. of the Massachusetts Association of Boards of Health, vol. viii., 10 1898.Google Scholar

² Wolff in 1895 examined bacteriologically the accessory sinuses of the nose in fatal cases of diphtheria etc. The B. diphtheriæ was found in 12 out of 22 cases of diphtheria in one or more of these sinuses, including once in the frontal, and six times in the sphenoidal sinus. Cited by Howard, and Ingersoll, . Am. Journ. of Med. Sciences. 05, 1898.Google Scholar