DISCOVERY OF THE GERM OF SWINE-PLAGUE. 
553 
withdrawn.* * * § It is plain that such tubes could be preserved in¬ 
definitely for examination without any suspicion of atmospheric 
contamination. The only change that could occur would be due 
to a continued multiplication—a kind of cultivation of the organ¬ 
isms which had existed in the blood of the living animal. 
Three separate outbreaks of swine-plague at widely separated 
points were investigated, and in everyone I found, by the method 
of study just referred to, that the virulent liquids contained 
micrococci, single, and in chains and clusters, but never rod 
forms, except in those cases where the tubes did not fill well, or 
where they were imperfectly sealed. And blood from the most 
perfect of these tubes, which contained no visible organisms but 
micrococci, produced unmistakable and severe cases of swine- 
plague in inoculated animals.f These were the first experiments 
in which the virulent material, preserved free from suspicion of 
atmospheric contamination, was shown to contain but a single 
species of schizophytes; and they were consequently the first 
which indicated any connection between the micrococci and the 
essential cause of this disease. 
Tn his fourth report, Dr. Detmers states positively that some 
of the swine-plague organisms develop a lasting spore, and are 
changed into a helobacterium. f But there is no account of any 
measures adopted to decide which of the forms observed in the 
impure liquids examined had existed in the body of the living 
animal; nor was there any substantial reason given for consider¬ 
ing the helobacterium as belonging to the same species as the 
micrococci, or, if they happened to be different, which, if either, 
was able to cause the disease. 
The same volume contains my report bearing the date of Jan. 
27, 1882. In this are details of successful inoculation experi¬ 
ments with the sixth pure cultivation of micrococci which had 
been obtained and cultivated with every precaution known to 
science at the present day.§ It was the first real evidence of the 
* Ibid ., p. 22. 
f Ibid ., pp. 23, 24. 
t Department of Agriculture. Annual report, 1881 and 1882. 
§ Loc. cit., pp. 267-269. 
