TRANSMISSION OF TUBERCULOSIS THROUGH MEAT AND MILK. 713 
man must; be informed that it is not to be had without direct 
experimental inoculation or experimental feeding of members 
of the human species with tuberculous products of animals. 
That this is not likely to be done'it is needless to state. It is 
not impossible that some one may apply to tuberculosis ex¬ 
periments of the same nature as those described by Arning 69 , 
in which a criminal was inoculated with leprous material. 
Certainly this sort of experimentation might be done in case of 
criminals, but such experimental work can never be done in 
case of children. Hence, the relation between the milk of tuber¬ 
culous cows and tuberculosis in children will never be decided 
on any evidence so positive as this. 
Adami 70 considers as doubtful the conclusion that there has 
been a causal relation between the milk used and the tuberculo¬ 
sis of the persons using it, or between the wounds' received 
while making autopsies and the subsequent tuberculosis in 
cases such as those cited in this article. He bases his opinion 
on the fact of the impossibility of total exclusion of all other 
sources of infection. One who puts forth such a statement as 
an argument does not realize the abyss of fatalism into which 
he would plunge science in all attempts at discovering the 
source of infection in case of any of the infectious diseases ; 
especially would this be the case in such a chronic disease as 
tuberculosis. If the argument were valid, it would apply to all 
diseases. It is not possible to absolutely and totally exclude all 
other sources of infection in any case. To do this would de¬ 
mand on the part of the experimenter and observer a knowledge 
of all possible sources of infection, other than the one under 
consideration, that might be active in a given case ; and, further, 
a knowledge of altogether hidden and entirely unknown causes 
which might act. Unless this were done the same objection 
might be raised, viz. : The other causes have not yet all been 
excluded ; there may be some source of infection of which 
neither you, nor I, nor any one else has any knowledge. Re- 
ductio ad absurdum ! All we can do, and all that it is necessary 
to do, is to exclude all known or probable sources. We must 
