BUBONIC PLAGUE. 561 



ease, but also of curing it in mice and guinea-pigs and 

 probably in man. 



Haffkine in his experiments followed the line of pre- 

 ventive inoculation as employed against cholera. Bouil- 

 lon cultures were used in which floating drops of butter 

 were employed to make the islands of plague bacilli 

 float. The cultures were grown for a month or so, suc- 

 cessive crops of the island-stalactite growth as it formed 

 having been precipitated by agitating the tube. In this 

 manner there was obtained an "intense extra-cellular 

 toxin" containing large numbers of the bacilli. The 

 culture was killed by exposure to a temperature of 70 

 C. for one hour, and the mixture used in doses of about 

 3 c.cm. as a preventive inoculation. 



The most interesting collection of statistics, showing in 

 a most convincing manner the importance of the Haff- 

 kine prophylactic, is that of Leumann of Hubli. The 

 figures, together with a great deal of interesting informa- 

 tion upon the subject, can be found in the paper upon 

 " A Visit to the Plague Districts in India" by Barker 

 and Flint. 1 



The immunity conferred by the Haffkine prophylactic 

 in doses of 1 c.cm. is of considerably longer duration, 

 lasting about a month. The preparation must not be 

 used if the person have already been exposed to infection, 

 and is possibly in the incubation stage of the disease, as 

 it contains the toxins of the disease, and greatly intensi- 

 fies the existing condition. When injected into healthy 

 persons it always produces fever, local swelling, and ma- 

 laise. 



Wyssokowitz and Zabolotny, 2 whose studies have 

 already been quoted, used 96 monkeys in the study of 

 the value of the "plague-serums," and found that 

 when the treatment is begun within two days from the 

 time of inoculation the animals can be saved, even 

 though symptoms of the disease are marked. After the 

 second day the treatment cannot be relied upon. The 



1 New York Medical Journal, Feb. 3, 1900. * I.oc. cit. 



36 



