ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 481 



secutive summers, investigated the resisting powers of the Skiga-Flexner 

 dysentery bacillus against winter frost. The method he adopted was to 

 inoculate samples of garden earth mixed with urine and faeces, slices of 

 potato, tap water, sterile water, coffee, coffee with milk, coffee with 

 sugar, &c, with pure cultures of the B. dysenteries, and to expose this 

 infected material, together with pure cultivations on agar and in broth, 

 in an open wooden box in the open air every frosty uight from Dec. 19, 

 1901, to Feb. 24, 1902. Control series of cultures were maintained 

 during this period at the ordinary room temperature. 



Exhaustive observations were carried out on Dec. 29, and on the 

 27th of the following February, with the result that from the agar and 

 broth cultures and from the infected coffee and milk, whether exposed 

 to the cold or kept at the room temperature, pure cultivations of typical 

 dysentery bacilli were recovered, and their identity carefully confirmed 

 by subcultivation on the various media. In the garden earth, potato 

 slices, and various coffee preparations, the B. dysenterise was, however, 

 so overgrown by the multiplication of ordinary saprophytic bacteria, 

 oven at the first observation (Dec. 29), that it could not be detected, and 

 was considered to have already died out. 



Diphtheria Toxins in Serum Media.* — C. Wood, by cultivating the 

 B. dijjhtlierise in natural unchanged albumen (e.g. blood-serum) derived 

 from the horse (homeoplasma), prepares a toxin which, when injected 

 into horses, provokes a rapid rise in the antitoxic value of their serum. 

 In the author's method of preparing the toxin he inoculates ordinary 

 alkaline peptone broth with a virulent B. diphtherise and incubates at 

 37° C. for a week or more ; then adds 15 to 30 p.c. of its bulk of sterile 

 horse-serum, and again incubates at 37° C. for a month or six weeks ; 

 then raises the temperature of the cultivation to, and maintains it at, 

 65° C. for one hour, and finally filters it through a Chamberland filter 

 candle. If, however, the serum from some other species of animtl 

 (heteroplasma), such as the sheep, ox, or man, is employed in the culture 

 medium, no such rise in antitoxic value takes place. 



The author next extended his experiments to the ordinary laboratory 

 animals — rabbits, guinea-pigs, and pigeons — and found that preliminary 

 injections of rabbits and pigeons with toxines obtained from media con- 

 taining guinea-pig's serum, so far from protecting the animals against a 

 lethal dose of toxin, appeared to render them more susceptible ; but 

 guinea-pigs were rendered more resistant or entirely protected. When 

 rabbit serum toxin was used, only the rabbit was rendered more re- 

 sistant. On the other hand, pigeon serum toxin appeared to increase 

 the resistance of rabbits and guinea-pigs as well as pigeons, although 

 this anomaly might be explained as a matter of dosage. 



Bacillus diphtherise in Simple Rhinitis.! — Neumann, from a study 

 of five cases of what proved to be nasal diphtheria, concludes that the 

 occurrence of virulent diphtheria bacillus in cases of apparently simple 

 rhinitis is much more common than is generally supposed. The fact 

 that t these cases are so frequently overlooked is due to the want of 

 uniformity of the symptoms and the mildness, as a rule, of the attack. 



* Centralbl. Bakt., 1* Abt., xxxi. (1902) pp. 241-5. 

 t Tom. cit., pp. 34-41. 



