150 Spirocliaetae and Acanthia 
In stained films the majority of the spirochaetes appeared normal 
up to 
96 hours at 12° C., they disappeared after 120 hours. 
45 „ 25° C. „ „ 72 „ 
Some dividing forms were detected after 22 hrs. at 12° C. 
The red blood corpuscles could be discerned after 
96 hours at 12° C. 
45 „ 25° C. 
A positive infection experiment by means of A. lectularia. 
3. iv. 1908. Seventeen bugs were allowed to feed on an infected 
mouse (A) showing many Sp. obermeieri in its blood. The bugs were 
allowed to feed partially for about 5 minutes and were then transferred 
directly to a normal mouse (B) upon which they fed to repletion. 
6. IV. 1908. Eighteen bugs fed similarly on an infected mouse (C) 
and immediately afterwards on mouse (B). 
4—14. iv. 1908. The blood of the mouse (B) was examined for 
spirochaetes on 11 successive days with negative results. 
15. iv. 1908. Spirochaetes were found in small numbers in the 
blood of mouse (B). 
27. iv. 1908. Mouse (B) was found dead, no spirochaetes were 
found on microscopic examination but their presence was proved by the 
inoculation of the mouse’s spleen pulp and blood into another mouse, 
which showed spirochaetes in its blood 9. v. and died 10. v. 1908. 
Conclusions (II). 
The foregoing experiments, whilst not sufficiently numerous to 
permit of any final conclusions, appear to indicate that Spirochaeta 
obermeieri may die out more rapidly than Sp. duttoni in the gut of the 
bug. It is possible that the bugs digested their food more rapidly 
owing to their being more hungry than the lot used for experiments 
with Sp. duttoni. The experiments are being repeated. 
It has been demonstrated by one experiment that Acanthia lectularia 
fed on an infected mouse and immediately afterwards upon a healthy 
mouse is capable of transmitting the spirochaete. 
