Bakewell. — 0)1 Vaccination. 635 



cows with human small-pox, and obtained vesicles of modified 

 small-pox, from which he vaccinated children. This form of 

 vaccine proved much more powerful than the Jennerian vac- 

 cine, and was very extensively used. I procured a supply 

 from Mr. Marson when I was Vaccinator-General of Trinidad, 

 and introduced it into the island ; many thousands of children 

 were vaccinated from it. 



It is important to remember, in the discussion of this 

 question, that vaccine, generally speaking, is only modified 

 small-pox. The reason, and the only reason, for vaccinating 

 infants is to prevent their having natural small-pox ; in 

 other words, the law compels them to sufi'er a mild form of 

 small-pox, inoculated, in order to prevent them from having 

 small-pox in the natural way by ordinary infection. This 

 procedure is vindicated on the ground of public safety, and 

 an appeal is made to the experience of former days, before 

 vaccination was introduced, to show the terrible ravages com- 

 mitted by small-pox, and the comparative immunity created 

 by vaccination. 



In my younger days it was contended boldly that a 

 thoroughly successful vaccination, leaving four good and 

 characteristic scars, was an all but absolute preventive of an 

 attack of small-pox for the whole of life. Nobody maintains 

 this view now. It was Marson' s view, supported by statistics 

 which he had gathered from his experience at the Small-pox 

 Hospital, London, and from other sources. With two good 

 marks, the mortality was only 3' 6 per cent. ; with three 

 marks, 3-1 per cent.; and with four marks, 1-6 per cent. 

 But it is to be noted that in 1876-78 the mortality among 

 persons having four marks was 3-1 per cent, at the Hamp- 

 stead Hospital, one of the finest hospitals in the world, in a 

 magnificent situation, and with every possible aid that medical 

 skill could afford. Now, 3 per cent, of deaths in an acute 

 disease, tending to terminate in health, and among patients 

 having all the advantages just enumerated, would serve to 

 show that there is very little protective influence in the vac- 

 cine itself. In an epidemic of typhoid in a tropical climate, 

 amongst patients mostly of the lowest class in the community, 

 living in the most insanitary dwellings, badly fed and badly 

 nursed, I have had a mortality of only three out of ninety- 

 three cases, or 3-2 per cent. I have had a mortality of only 

 4 per cent, in an epidemic of acute scorbutic dysentery in the 

 same colony among 111 patients. So that a mortality of 3'1 

 per cent, does not imply any specially protective power over 

 those attacked. 



But does vaccination protect the vaccinated person from 

 an attack of small-pox ? In other words, if a thousand vacci- 

 nated persons and a thousand unvaccinated, living under 



