140 Proceedings of Royal Society of Edinburgh. [sess. 
scientist emphasises this expression of opinion in the Harben 
lecture * delivered by him in London, and condemns the practice of 
inoculating with Haffkine’s fluid those who have been in contact 
with a plague case. These opinions he founds on laboratory ex- 
periments only, never having had an opportunity to use the plague 
vaccine during an epidemic among human beings. It is well 
known, however, that the immediate effect produced by the action 
of a microbial virus varies with each species of animal operated on, 
and that quite as various degrees of immunity are produced in 
them by this means, so that it is impossible without trial to pre- 
dict what the exact action on any fresh species may be. We must 
take experiments on animals as an indication merely of what may 
be expected if the same procedure be applied to man, and it is 
quite legitimate, therefore, to set aside this dictum of Calmette’s 
if we find from the examination of a sufficient mass of evidence 
derived from human beings that there is no harm apparent to 
those inoculated during the incubation stage of plague. 
Inoculations have been carried out on a large scale in various 
parts of India, hundreds of thousands of persons (over 200,000 in 
Bombay city alone) having been operated on during the last four 
years. From the reports sent in from certain prisons and small 
villages, where accurate statistics have been kept, it has been 
found possible to compile the following table showing the case- 
mortality in persons inoculated during the incubation period of 
plague. These figures include all instances known to us in India 
where statistics have been kept with sufficient accuracy to admit of 
the extraction of this information.! 
* Brit. Med. Journal , 24th November 1900. 
t For full table, showing separately for each place the results obtained, 
vide Brit. Med. Journal of 14th September 1901. 
[Table. 
