THE 



POPULAR SCIENCE 



MONTHLY. 



JUNE, 1900. 



PKEVENT1VE INOCULATION. (I.) 



By Dr. W. M. HAFFKINE. 



1>1 RECTOR-IN-CHIEF, GOVERNMENT PLAGUE RESEARCH LABORATORY, BOMBAY. 



IT was due to certain particularly favorable circumstances that the 

 first ideas on preventive inoculation were gathered from observa- 

 tions on smallpox patients. Such circumstances were presumably the 

 following: 



a. It is a disease which attacks epidemically, in a short time and 

 within a small area, large numbers of people, thus permitting of 

 easy comparisons and suggesting conclusions from the facts observed. 



b. Its fatality is comparatively small, so that after each outbreak a 

 large number of convalescent persons remain alive to serve as objects 

 for future observation and comparison. 



c. These convalescents are marked and are thus easily distinguish- 

 able from the rest of the population who have not been attacked, and 

 even the severity of the disease they have gone through is, so to say, 

 written down on their faces and bodies. 



d. The disease is easily communicable, owing to the infectious 

 matter appearing on the surface of the patient's body in the pustules. 



It was easy, therefore, to notice in this case, as was indeed very early 

 done in the East, that a person who has gone through one attack, as 

 shown by his pitted face, very rarely suffers even during severe subse- 

 quent epidemics. Smallpox, like other epidemic diseases, breaks out in 

 some years in very fatal, in others in milder forms. It is admissible that 

 by a mixed process of thought and faith an impression insensibly gained 

 ground that it was lucky to have been touched by the smallpox deity — 

 of course, not in years when that deity appeared in terrifying mor- 

 tality. Accordingly, in times of mild outbreaks people would not be 



