110 
D. E. SALMON. 
even germinates after passing through the entire digestive tract 
of a large animal like the ox, or after having been buried in fer¬ 
menting manure for a considerable time. The rods, on the other 
hand, show an active form of life, and may be compared to the 
growing maize plant, which is so easily destroyed by frost or 
drought, and to the existence of which the sun and air are so 
necessary. That is to say, a spore or seed retains its vitality, and 
is capable.of growth and reproduction after having been exposed 
to conditions which would assuredly destroy the life of the grow¬ 
ing plant or fungus. I ask the closest attention to this point, 
because it is from this fact that I hope to convince my readers of 
the connection between the Bacillus anthracis and the contagium 
of charbon. It is the line of argument originally used by Koch, 
and to me it seems to be a perfect demonstration. 
By the cultivation of this organism on growing slides, it was 
found that it could not form spores unless the atmospheric air 
was freely admitted ; it also required for this purpose a tempera¬ 
ture above 12° (53.6° F.) If the conditions of temperature, ven¬ 
tilation and concentration of nourishment were such that spores 
could not be formed, the rods perished in a few days. Now, it is 
a most interesting question to know if the activity of anthrax 
virus disappears with the death of the rods when spores are not 
formed, and if it is preserved indefinitely after the formation of 
such spores; and this question is doubly interesting because the 
conditions which affect the death of the rods before spore-for¬ 
mation are such as will preserve unstable chemical compounds. 
For instance, such a chemical substance is best preserved by cold 
and protection from atmospheric oxygen, as well as by drying; 
but these conditions prevent the formation of bacillus spore, and, 
hence, lead to the death of the organism in a very short time. 
If, therefore, the activity of fresh charbon blood (which only 
contains rods) is lost in a few days when exposed to a low tem¬ 
perature, if it is similarly lost when hermetically sealed in glass 
tubes, or quickly dried, especially if the loss of activity corres¬ 
ponds with the death of the rods as determined by microscopical 
observation and cultivation-experiments, we have good evidence 
that this activity is due to the Bacillus. If we can go beyond 
