1910.| Hapervmental Treatment of Trypanosomiasis. 145 
No. of ae Material used, and quantity. aelay Remarks. 
3 5 m. 5 per cent. lith. ant. tart., | Died on 116th day. Recurrence 
1 intravenously | i } occurred on the 115th day, when 
1 30 mg. ant., intravenously ......: the impure metal was given. 
3 30 mg. ant., intravenously ...... . 
21 1 30 tl ant., intraperitoneally... \ one qed ore ney 
2 60 mg. ant., intravenously ...... | — | Died on 188rd day, probably killed 
with impure antimony. Had in- 
creased 300 gr. in weight. 
4 2 30 mg. ant., intravenously ...... — | Died on 147th day, probably as 
No. 8. Had increased 180 gr. in 
weight. 
3) 1 30 mg. ant., intravenously ...... i Died on 79th day. Lost 500 gr, in 
weight. 
Hapervments with Surra Rats after One Dose of Antimony. 
We have had the following curious experience with infected rats which 
had been treated with one dose of lithium antimonyl tartrate. One dose of 
this drug causes the disappearance of all trypanosomes from the blood, and 
keeps the blood free from them for a variable period, the average time of 
recurrence being 18 days. We wished to find out how soon the blood of 
a rat thus treated became infective to other rats on sub-inoculation, and 
whether it would prove to be so before trypanosomes could be found in it 
by ordinary microscopic examination. Sub-inoculations were therefore made 
from the treated rat’s blood at various intervals from the 2nd to the 
16th day after the one dose of antimony. It was then found that the 
blood of the original rat was infective long before any trypanosomes could 
be found in the peripheral circulation; but also that this infectivity was 
not constant, an infection being produced on one day, and none occurring on 
one or two subsequent days. Moreover, as the table shows, the course of 
the disease (incubation period especially) was very prolonged. Ordinary 
untreated infective blood produces in rats a recognisable infection in from 
two to four days, and death in from six to seven days. In these cases 
either the trypanosomes could not be found in the peripheral blood at all, 
the only lesion being the very large spleen, or were not found until the 
28th day after inoculation. These prolonged incubation periods appeared to 
have no relation to the time of the recurrence in the original rat, and the 
infection was brought about by blood which not only showed no trypano- 
somes, but appeared to be perfectly normal in structure. We have no 
explanation of these results, but as all the rats which died had very large 
spleens we can only suppose that the trypanosomes were present in either 
some form or place which we did not recognise or find. If this be so the 
