THE BIOLOGY OP DAILY LIFE. 109 



experience as to the best modes of propagating disease 

 by observing the effects of vaccination. 



Vaccine lymph, according as it is more or less pure, 

 is, in like degree, a more or simple cultivation of the 

 leucocyte. 



It will not, I hope, be regarded as a wanton experi- 

 ment in disease-production that once or twice brewer's 

 yeast has been used for vaccination. I have never 

 tried this experiment myself. In my student days I 

 have vaccinated very many hundreds of children, but 

 then I did it, as many others do who follow the 

 ordinary medical teaching and practice, without in the 

 least knowing the horrible nature of these acts. Now 

 nothing would induce me to pollute with the unclean 

 thing the opening promise of an infant's life. 



A short quotation gives the result of a sort of experi- 

 ment which will, I hope, never need to be repeated : 



" The inoculation of brewer's yeast into the 

 blood will produce similar results " [to the in- 

 oculation of leucocytes] (see Phys., p. 112). 



(6.) 



THE LEUCOCYTE AND " PUS." 



" Pus, or the matter which we see in boils, 

 ulcers, and abscesses, is nothing but the white 

 corpuscle variously modified by stagnation, 

 position, influence of the temperament of the 

 individual, and the effects of drugs brought to 

 bear upon the organism, whether we see it in 

 an irregular mass, or simple germinal matter, 

 and when boils, eruptions, or ulcers form on 



