^Jo^S^CS^MsS'l Cfreai Pathological Processes. 17 
were pure albinos, that is to say, having no coloured hair whatever 
on the body, and perfectly unpigmented eyes. This is a circum- 
stance to be remembered, as we are told in connection with experi- 
ments on the excision of the supra-renal capsules that albinos have 
a physiological economy differing in some respects besides the 
chemistry of pigment from that of other animals not albinos. Some 
pathologists are inclined not to attribute any importance to that 
statement and to doubt its purport ; but I mention it in order that 
your view should be perfectly open to that point. It must, how- 
ever, be noted that one of the mice which died was grey and white, 
but, as it was bred from albino stock by crossing with a rare variety 
of tame mice, it forms a singular exception to the fact tha,t the 
animals employed were albinos. 
I have a detailed statement concerning the animals experi- 
mented upon, but will only trouble you with the gross results. 
Total number of animals 51 
Total number of sick 13 
Total number of deaths 11 
Eecovered 2 
Not affected 38 
51 
The observer is struck with the peculiarly small number of re- 
covered animals, compared with the number which died. Eleven 
deaths out of thirteen sick, is a proportion which is very much greater 
than the mortality in men. In men ordinarily one half of those 
affected die. Most remarkable, however, is the circumstance that, 
out of the eleven deaths, ten occurred to pairs of which each were 
living in a cage together, and that these deaths of the individuals 
of each couple took place almost at the same time. This points to 
a very definite cause of disease, — a simultaneous introduction of its 
poison, and a great similarity in the manner in which animals 
susceptible of it reacted upon it. The cause of the immunity of 
other animals, apparently subject to the same influences, remains 
a secret, just as hidden as the cause of the immunity of many 
men in epidemic times. The majority of men in epidemic times 
are not affected by the disease, but only a small proportion ; and 
this peculiar liability we cannot explain at present. We call the 
exemption of those who are not affected " the immunity," and the 
opposite " the hability " — a disposition or pre-disposition caused by 
the individuahty, by the time, and by the place in which he lived. 
I recommend you to study the researches of Dr. J. B. Sanderson 
on the entire subject of cholera infection, and the very complete 
account of the literature of the subject which he has given in his 
Keport to the Medical Officer of the Privy Council. 
The evidence which I have laid before you is collateral, and not 
VOL. I. c 
