364 IMPORTANT VARIETIES OF FISSION-FUNGI. 



man arises, after destruction of the epithelial lining of the 

 intestinal canal, by the enormously multiplied vibrios and 

 the accompanying intoxication and absorption of poisons 

 from the dead vibrios. We cannot here enter into a dis- 

 cussion of the teachings of Buchner, Nencki, and Metsch- 

 nikofT, that the immunity against cholera in many 

 localities is always or often dependent upon the absence of 

 a synergetic or upon the presence of an antagonistic 

 micro-organism in the intestine of the host. 



Immunity and Immunization. Recovery from 

 cholera or an artificial cholera infection is followed by a 

 certain immunity. In the peritoneal cavity of such an 

 immunized animal cholera vibrios become granular and 

 die (p. 374). The serum of the animal contains agglu- 

 tinin (p. 374). With the cholera immune serum no con- 

 siderable passive immunity in other creatures can be 

 obtained, the conditions being very similar to those in 

 pest. 



On the contrary, Haffkine has obtained very good results 

 in India in the production of active immunity by means 

 of devitalized cultures. Kolle (Deut. med. Wochenschr., 

 1897) has repeated the experiments in the institute for 

 infectious diseases, and found them confirmed in so far 

 that the serum of the experimental persons contained bac- 

 tericidal substances after about five days, which were most 

 abundant on the twentieth day, but could also be demon- 

 strated after a year. Various materials were injected; for 

 example, one- tenth of an agar culture suspended in bouillon 

 and heated for one hour to 56. Virulent cultures operate 

 similarly to non-virulent ones. For two or three days 

 there is quite a painful infiltration at the point of injec- 

 tion. For the entire literature regarding cholera immu- 

 nity see Voges (C. B. xix, 466). 



Varieties and Variations of the Vibrio cholerae. 



Since first D. Cunningham (C. B. ix, 763, also xxm, 854) demon- 

 strated a considerable variation in cholera vibrios which he cultivated 

 from typical cases of cholera, many writers have described forms which 

 in part deviate very much. We can here only mention a few of these 

 experiences, and only those where it appears certain that vibrios from 

 true cases of cholera were in question. 



A series of forms have been accurately described and photographed 



