6
in about 39 hours. Animals of the above body-weight subcutaneously injected
with 5 c.c. of a 1 per cent. solution always recover, without the exhibition of
serious symptoms.
Guinea-pigs of 200 grammes body-weight always succumb to doses of
2.5 c.c. of a 1 per cent. solution of atoxyl in about 51 hours.
Lethal dose of atoxyl for healthy equines.
IN THE PLAINS.
24. (a) Mules.—Eight grammes of atoxyl per 400 lbs. body-weight, when
injected into an animal of 504 lbs. body-weight, produced symptoms of slight
colic, which soon passed off and the animal recovered.
Nine grammes of atoxyl, per 400 lbs. body-weight, when injected subcuta-
neously into an animal of 497 lbs. produced severe colic after 52 hours, and
death in 84.5 hours.
IN THE HILLS.
Eight grammes of atoxyl, per 400 lbs. body-weight, when injected
subcutaneously into mules of 540 and 584 lbs. brought about a fatal termina-
tion, in about 47 and 85 hours, respectively.
(b) Australian Mares.—Fifteen grammes of atoxyl in 2 per cent. solu-
tion produced no symptoms when injected subcutaneously into an animal
body-weight 966 lbs.
A dose of 18.14 grammes in a 2 per cent. solution, injected into an animal
of like body-weight, brought about severe symptoms of colic in 15 hours, but
recovery followed ; whereas 21.32 grammes in a 2 per cent. sulution, equiva-
lent to eight grammes per 400 lbs. body-weight, brought about in a mare of
1,066 lbs. body-weight a fatal issue in 18.5 hours.
The effect of different doses of atoxyl in animals the subjects of
spontaneous equine trypanosomiasis, and after a number of passages through
white rats.
IN THE PLAINS.
Rats
25. (a) Direct from the horse to white rat.—Positive results have been
obtained in all these cases in which 0.03 grammes of atoxyl (3 c.c. of a 1
per cent. solution) were injected primarily, when the trypanosomata were
swarming in the blood of the peripheral circulation.
(b) Rats inoculated with T. evansi, with virulent blood after the 67th
to the 71st passage.—A single dose of 0.03 grammes of atoxyl, showed no return
of the flagellates during the succeeding 181 days.
(c) After the 78th to the 82nd passages.—Such rats when injected with
0.3 grammes of atoxyl, always succumbed to its effects in a few days, nor could
animals of the same weight tolerate even a dose of 0.025, a fatal result always
following within twelve hours to several days.
IN THE HILLS.
Eighty per cent. of all white rats inoculated with equine trypanasomi-
asis, from the fortieth passage through the horse, when injected subcutaneously
with 3.0 c.c. of a 1 per cent. solution of atoxyl, at the time when flagel
lates were swarming in the peripheral circulation, have succumbed within
one to five days. A result exactly opposite to that obtained under similar
conditions in the plains.
Guinea-pigs.
A dose of 0.01 grammes atoxyl kept the trypanosoma in abeyance for a
period of sixteen days, while 0.02 grammes produced the same effect during
twenty-eight days in a second animal of about the same body-weight, 400
grammes. When, however, the above doses were followed respectively by
one of 0.03 grammes, in the former, death followed in thirty hours, while in
the latter, the flagellate again absented itself, during a period of ten days,
but death took place two days later.