404 PA THOGENIC BA CTERIA.

2. It may be due to the septicemias established during
the course of the disease, the cadaver then presenting an
almost pure culture of the other microbes.

3. It may be due in large measure to renal insufficiency,
when the cadaver is found nearly sterile.

The black vomit is due to the action of gastric acidity
upon the blood which has extravasated in the stomach in
consequence of the toxic products of the Bacillus icte-
roides.

The Bacillus icteroides produces a toxin the result of
whose action corresponds to the essential symptoms of the
disease. Animals immune to the infection, or only par-
tially susceptible to it, are not much affected by the toxin.
Susceptible animals, such as dogs, are profoundly affected.
Ten to fifteen minutes after injecting the toxin the
animals experience a general rigor; abundant lachryina-
tion begins, followed by continued vomiting, first of food,
then of mucus. In a short time the animals lie help-
less and extended. Hematuria frequently occurs. If the
dose be moderate, the dog recovers quickly from the
violent attack; but if the quantity of toxin be very large
or repeated on successive days, it finally succumbs, pre-
senting the anatomical lesions already described as due to
infection.

The proofs, of the specificity of the Bacillus icteroides
are not limited to the animal experiments quoted. Sana-
relli also adduces five experimental inoculations upon
men. These inoculations were not made with the bac-
teria—z. e. were not infection experiments—but were
made with the filtered sterile toxin, whose action could
be more easily controlled. u The injection of the filtered
cultures in relatively small doses reproduced in man
typical yellow fever, accompanied by all its imposing
anatomical and symptomatological retinue. The fever,
congestions, hemorrhages, vomiting, steatosis of the liver,
cephalalgia, collapse—in short, all that complex of symp-
tomatic and anatomical elements which in their combina-
tion constitute the indivisible basis of the diagnosis of