414 
THOMAS BOWHILL. 
with sterilized cotton, fill tubes about one-third, sterilize this 
mass once more by heat, using care, or the stiffening power of 
the gelatine will be destroyed. Agar. agar, is prepared in a 
similar manner, one and not over two per cent, being substituted 
for the gelatine. Agar. agar, makes a gelatine that can be used 
at any ordinary heat of summer without becoming fluid, whilst 
gelatine melts between twenty-five and thirty degrees cent. It is 
also of no use to increase the quantity of gelatine, as by doing so 
you do not get a proper development of the bacteria. Inocula¬ 
tions of these bacteria in gelatine gave peculiar colony-like devel¬ 
opments, somewhat resembling knots on a fine piece of thread, 
and not causing fluidification. There is nothing peculiar regard¬ 
ing their growth in agar. agar. When grown upon potatoes the 
culture is of a chromogenie nature, and becomes about the color 
of coffee when good cream has been added to it. 
Since 1878 an almost continued series of investigations into 
the cause and nature of hog cholera have been made under the 
auspices of the agricultural department of the United States, 
which are to be found in its reports. The first of these were 
made by Messrs. Law and Detmers. Law seemed to have con¬ 
sidered the disease to be due to a micro-coccus, quoting Klein in 
the following language, in the report of 1878: “Klein, who in 
1877, cultivated a micrococcus for seven successive generations 
and finally inoculated the fifth and seventh generations success¬ 
fully on two pigs, seems to have established that these microphytes 
are the ultimate cause of the disease.” Detmers, in the same re¬ 
port, seems to have thought that a bacillus was the cause of 
American swine plague, to which he gave the name of “ bacillus 
suis,” which he says u are found invariably either in one form or 
another in all fluids, in morbidly affected tissues and in the excre¬ 
ments (?) and constitute beyond doubt the infectious principle or 
produce the morbid processes if transmitted directly or indirectly 
from a diseased animal to a healthy one.” It is singular that 
both of these authorities should have received what appeared to 
be equally positive and confirmative results from two such en¬ 
tirely different organisms. The work of Law and Dr. Detmers 
is, however, entirely eclipsed by that of Dr. Salmon, who also 
