E. Hindle 
141 
and negative results, obtained respectively from the various parts of the 
ticks. 
Tick material injected 
Result of inoculation 
Coxal fluid + excrement (Exp. 1)1 
Gut + contents | 
8 + 
0- 
Malpighian tubules 
5 + 
3- 
Salivary glands 
2 + 
0- 
Sexual organs 
6 + 
2 - 
It is important to remember that in these experiments a negative 
result is much less liable to error than a positive one. Whilst isolating 
the various organs, it is almost impossible to prevent the contents of 
the gut from coming in contact with the other parts of the tick, and 
although the latter were always carefully washed to try to remove 
any such contamination, it is difficult to make certain of the removal of 
all traces of infective material from the outside of the organs. The 
two positive results which have been obtained with the salivary glands, 
in experiments 2 and 8, can be explained on the supposition that these 
organs were contaminated with the gut + contents. In experiment 2 the 
incubation period (6 days) of the mouse injected with the contents of 
the gut is exactly the same as that injected with the salivary glands; 
and in experiment 8 there is only two days ditference between the 
corresponding periods. 
Infectivity of the organs of ticks kept for some time previous to dissection 
o,t a high temperature (35—37° C.). 
Exp. 12. (Nuttall and Eantham) 24. ii. 09. 0. moubata, small adult J , last fed 
12. XI. 08. Kept at a uniform temperature of 21° C.; finally, for 20 hours at 37° C. 
Tick material injected 
Result of 
inoculation 
Incubation 
period (days) 
Gut + contents 
+ 
10 
Malpighian tubules 
+ 
12 
Salivary glands 
+ 
10 
Testis 
+ 
10 
Exp. 13. (N. & F.) 25. ii. 09. 
0. moubata, small adult J, last fed 12. 
XI. 08. Kept 
a uniform temperature of 21° C. 
; finally, for 44 hours at 37° C. 
Result of 
Incubation 
Microscopical 
Tick material injected 
inoculation 
period (days) 
examination 
Gut + contents 
+ 
6 
+ 
Malpighian tubules 
+ 
(5 
+ 
Salivary glands 
+ 
8 
- 
Testis 
+ 
5 
+ 
