On Preventive Inoculation. 



263 



Of the twelve prisoners in the uninoculated group who developed 

 plague during the next few days after the date of inoculation a large 

 proportion, if not all, must have been already incubating the disease 

 on that day ; and seeing the perfect similarity of conditions under 

 which the inoculated and the uninoculated, who belonged to the same 

 crowd of people, were living, one could infer safely that a similar group 

 of individuals incubating plague was present among the inoculated 

 also at the time when the inoculation was performed on them. 



The inoculation, however, did not aggravate their condition, as the 

 number of inoculated who developed plague, counting from the first 

 twelve hours of inoculation, was proportionately five times smaller 

 than the corresponding number among the uninoculated ; and the two 

 cases that appeared among the inoculated, one on the very next morning 

 after inoculation, both ended in recovery. 



As far as that first experiment went, therefore, men behaved like the 

 laboratory animals upon which the prophylactic properties of the drug 

 had been worked out. 



For communicating that protection one injection of prophylactic 

 appeared sufficient, with a dose of 3 c.c, which dose, however, in our 

 subsequent operations was further reduced to 2J c.c. 



The difference in favour of the inoculated appeared within some 

 twelve hours after the operation ; but the man who was inoculated with 

 plague on him, and the two who developed clear symptoms of plague 

 the same evening, did not benefit by the operation. 



This completed the first information gathered with regard to five of 

 the six questions enumerated above. No answer could be given as to 

 the final duration of the effect of inoculation, except that the operation 

 appeared to be useful in a localised already existing epidemic, extending 

 over seven days. 



The Experiment in the Umerkadi Common Jail, Bombay. 



In the next case the strictness of the conditions of the last experi- 

 ment was enhanced further. This was in the second Bombay jail, the 

 Umerkadi Common Jail. 



The plague broke out there at the end of December, 1897, and by 

 the 1st of January three prisoners were attacked and all of them sub- 

 sequently died. 



In the interval between the operations in the two jails, some 8000 

 people in the free population of Bombay had already availed them- 

 selves of the inoculation. 



This time the whole of the prisoners, numbering 401, appeared willing 

 to undergo the preventive treatment. In view of the novelty of the 

 operation, however, and of our responsibilities before the government 

 and the public, and the necessity of demonstrating clearly the effect of 



