346 Col. Sir D. Bruce and others. Infectivity of |Nov. 25, 
The following table shows the result of the individual experiments as 
carried out with Lake-shore flies :— 
Table L.—Glossina palpatis and Trypanosoma gambrense. 
: Incubation 
Date: Expt. No. N 0. es ne ae No. aca yqithe period 
infected feed. injected. in monkey. 
1909. 
Misr yl Ore ares 521 %& hour 2 8 days. 
Jan. Gre 420 Be 2. 1 = 
ei BGs 421 aes 2 a 
Feb. 18 ...... 518 : ee 2 _ 
Mar. 19 22... 604. i se 2 + Gis 
ae LO ene te 605 13 hours 2 + Giy 
Hebaiis 70 519 ou tie 2 = 
June 22 ...... 1038 ED as 1 + Gr. 
Me LOo ye. 1043 Boras 1 i“ Bias 
Mar. 29 ...... 622 Anas | 8 + Tas 
June es. 4 984: i ae 5 + 8: 4) 
pie lu ea 1009 Ais ies 5 + 6-5, 
ne EoD be 1039 Gear 1 4 6a 
OZ) cee 1044: che Wye 1 + 64.355 
Sy RDAs 1045 iter 1 + OFe5 
cp) 190 pape 1041 Situs: 1 fe Oe 
ee) ae 1046 Bu es 1 2. 10°, 
ht A Cees 1042 Se 1 + ee 
fo Oe ee: 1047 oO Ae 1 + 9. <3 
ae oO ORN 1154 16) 3 1 2 
5s eee Las 1155 Gea, 1 -- 
pete OU 1156 7 ane 1 + 13uie 
ey ete it: 1157 Yea pen 1 — 
et 2O mt. 1158 TS y ys 1 + 93 
ie 1 oo 1159 Sime 1 + ies) Ss: 
Mar520 v2.0.0: 600 OTe 5 -- 
June 26" cee 1161 19, 7, 1 - 
Misr? 7425.45 524 23. ine 6 — 
Seaman A 585 BAY on * 6 - 
Remarks.—Twenty-nine experiments were carried out with Lake-shore flies and Trypanosoma 
gambiense. Eighteen of these experiments yielded a positive result, and were almost uniformly 
successful up to 18 hours after the infected feed. 1t seemed to be immaterial whether the fly 
was introduced whole or whether the alimentary canal alone was injected. In several instances 
where the gut of the fly was examined in the fresh state, swarms of flagellates natural to the fly, 
t.e. Trypanosoma grayi, were found, but their presence did not appear to modify the virulence of 
Trypanosoma gambiense. 
The following table shows the result of the experiments as carried out 
with laboratory-bred flies :— | 
