28 i 
Three rats, after the atoxyl, each received 27 cm of perchloride in four doses 
on the fifth to eighth days after inoculation. Trypanosomes were not again seen in 
any of them. One rat died (spleen enlarged, cause of death ?) 20 days after 
inoculation; the remaining two are alive 123 days after inoculation. Mice 
inoculated from them 98 days after inoculation were not infected and are still alive. 
Experiment (294).—The treatment of six rats was commenced on the fourth 
day after inoculation ; their infection was heavy and two died on the fifth day. 
The remaining four rats received 1-40.cm. of atoxyl in three doses on the fourth, 
eighth and tenth days after inoculation. Two rats had no further treatment ; 
trypanosomes reappeared in them in 34 and 41 days after the cessation of treatment. 
They died two to four days later (53 days after inoculation). 
In two rats atoxyl was supplemented by 27 c.cm. of perchloride given in four 
doses on the fifteenth to nineteenth days after inoculation. Trypanosomes have 
reappeared in neither of them. On the thirtieth day after inoculation one of these 
rats died (cause of death ?) ; after the second dose of atoxyl this animal had 
shown very marked signs of intoxication. The remaining animal is still alive 95 
days after inoculation. A rat and mouse sub-inoculated from it 43 and 70 days 
after inoculation are alive and uninfected. 
Experiment (296). — Four out of 12 rats died during the night of the second 
day after inoculation. On the third and fourth days the remaining eight received 
ic.cm. of atoxyl in two doses. Four rats received no further treatment ; one of 
them died almost immediately. Parasites reappeared in the other three in from 
to to 41 days after the cessation of treatment and all died in from 16 to 49 day's 
after inoculation. 
On the fourth, eighth, tenth and eleventh days after inoculation 27 c.cm. of 
perchloride was given in four doses to each of the remaining four rats ; one died 
[intoxication ?) after the first dose. All of the three rats were negative until 36 days 
after inoculation, when trypanosomes reappeared in one of them. The other two 
are still negative at 84 days after inoculation ; mice sub-inoculated from them at 
59 days after inoculation have not shown trypanosomes. The rat in which trypano¬ 
somes reappeared received 1 c.cm. of atoxyl in two doses on the day its relapse 
was detected, and the second day after. It then received 17 c.cm. of perchloride 
in three doses on the fifth, seventh and ninth days after the relapse. Parasites 
again reappeared in 14 days after the relapse. Atoxyl was again immediately given 
(ic.cm. in two doses on successive days) ; the trypanosomes disappeared as usual 
from the peripheral circulation. The animal died unexpectedly seven days later. 
Trypanosomes had not reappeared in its peripheral blood ; spleen and lymphatic 
glands were enlarged. 
This is the only instance of a recurrence of trypanosomes after a 
satisfactory combined treatment by atoxyl and mercury. In this 
experiment treatment was certainly commenced very late. There 
Was a smaller interval between the administration of the two drugs 
than is usual; but there were probably no infective trypanosomes left 
ln Ae peripheral circulation after the atoxyl treatment, since a rat 
subinoculated at that time has not shown trypanosomes and still lives. 
Experiment (297).—On the third and fourth day after inoculation 10 rats 
received ic.cm. of atoxyl in two doses ; two rats died during the night of the third 
da - v - Four rats received no further treatment. Trypanosomes reappeared m them 
frnra 13 to 24 days after the cessation of treatment and they died two or three 
da ys later. 
