VIRULENCE OF BLOOD AND MUSCLES IN TUBERCULOSIS. 23 7 
self previously described, there is brought out a total of 82 
experiments, of Avhich 52 were negative and 30 positive. 
Now, if it were a fact that out of 82 cases of bovine tuber¬ 
culosis selected at random in the slaughter-houses the blood 
had been proved virulent in 30 cases, hardly any one dare 
raise his voice against the general enforcement of total seizure. 
But at the same time it is right to observe that this would by 
no means prove that the risk of human infection from tuber¬ 
culous carcases, even with partial seizure, would be great, for 
it hardly needs to be pointed out that the subcutaneous or 
intra-peritoneal inoculation of relatively large quantities of 
blood is probably a much more certain method of infection 
than the ingestion of under-done or even raw flesh, and that 
the guinea-pig and rabbit are probably much more easily 
inf< cted than human beings. 
But when the particulars of the cases cited in M. Butel’s 
table are examined the evidence in support of the frequent 
virulence of the blood is found to be much weaker than it 
appears at first sight. The majority of the experiments 
quoted were made not with the blood of bovine animals but 
with that of small rodents, and it is quite inadmissible to 
immediately apply positive results obtained in the rabbit or 
guinea-pig to animals of the ox species. No one familiar 
with the common course of a tuberculosis infection in rabbits 
and guinea-pigs can deny that in these animals the blood 
within a comparatively short space of time becomes con¬ 
taminated with the bacilli. The distribution of the tuber¬ 
culous lesions in the viscera leaves no doubt on that head. 
But the march of events is very different in the bovine 
species; in them the progress of the primary lesions is in 
comparably slower, and it is only in quite exceptional cases 
and at a late stage in the disease that the lesions assume a 
distribution such as is almost constant’ in the guinea-pig or 
rabbit within at the most a few months after infection. Again, 
experiments made with the blood even of a bovine subject* 
provided that the lesions are those of a general miliary 
tuberculosis, are beside the mark, for no one disputes the 
necessity of total seizure in such cases. 
