H. L. Duke 
371 
P 277, infected from M 88, i.e. direct transmission of mainland wild-fly 
strain, showed, in 100 individuals counted, seven with the macronucleus in 
the posterior, and four with it in the anterior quarter of the body. 
Thus the antelope strain, the mainland fly strain, and the Damba wild-fly 
strain have shown posterior-nuclear forms in guinea-pigs; and the mainland 
fly strain, after one cyclical passage through laboratory-bred flies and sub¬ 
inoculation into D 281, showed a single example after prolonged search in 
a slide swarming with trypanosomes. 
( e ) Action of human serum. 
The 1912 Damba antelope strain showed no response to human serum. 
With the 1920 strain a few controlled inoculation experiments into guinea- 
pigs and rabbits were performed in which the serum was either mixed with 
the inoculum and injected at once, or else injected half an hour before the 
trypanosomes. No protective action was observed. 
Experiments in vitro , with and without the addition of fresh guinea-pig 
complement and at room and incubator temperature, also revealed no action 
on the trypanosomes by either human, mangabey, or lizard serum. 
Similar experiments with the Damba fly strain were also negative. 
(/) The behaviour of a black mangabey (Cercocebus albigena, sub sp.), obtained 
from the Kyagwe forests, towards the trypanosome used in these experiments. 
This species, of which there were three individuals at the laboratory, has 
proved very resistant to the various strains used. Two out of three have 
shown trypanosomes in their blood at rare intervals during prolonged daily 
examination both by fresh and stained thick film. The history of the three 
individuals is as follows: 
No. 114. (a) Interrupted feedings daily by 35 flies off Monkey 59 from 24. iii.-8. iv. 20. 
(6) Fed upon by positive flies of boxes 24 and 25 on 27. v.-29. v. 20. 
(c) Trypanosomes seen in very small numbers in monkey’s blood on 19. vi. 20. 
(d) Fed upon by clean laboratory-bred flies from 20. vi.-28. vi. 20. 85 dissected 
between 14th and 26th days after first feed: none found infected. 
(e) Negative to daily examination from 20. vi.-17. x. and from 20. x. 20.-5. iii. 21. 
Still alive and well. 
No. 112. ( a) Interrupted feedings off Monkey 72 with 35 flies from 22. iii.—30. iii. 20. 
( b ) Fed upon by positive box 77 from 9. xi.-lO. xi. 20. 
(c) Trypanosomes first seen in blood in very small numbers on 21. xii. 20. Between 
22. xii. 20 and 26. ii. 21 trypanosomes seen on 13 of the daily examinations. 
(d) Fed on by clean laboratory-bred flies from 24. xii.-29. xii. 20. 130 flies dissected 
after 7th day all nil: also from 29. i.—17. iii. 21 by other laboratory-bred flies 
of which 36 were dissected after 7th day; none of these flies was infected. 
Total 166. Still alive and well. 
No. 86. (a) Fed upon by 1171 wild lake-shore flies before its peculiar resistance wa^realised. 
( b) Fed upon by positive boxes 51, 52, 53 on 9. viii.-ll. viii. 20. 
(c) On 24. i. 21 inoculated with 1*5 c.c. citrated blood of Monkey 227 which showed 
trypanosomes (buck strain). 
( d ) Negative to trypanosomes in stained thick and fresh films from 30. iii. 20 to 
13. ii. 21. 
(e) Died 16. ii. 21. Spleen hard and small: blood inoculated half an hour after death 
into clean monkey which did not become infected. 
