Pathology. —The spleen is much enlarged and soft. 
The liver shows necrotic foci due, according to 
Levaditi, to an actual invasion of the tissue by spiro- 
chaetes. Stain sections of liver by Levaditi’s method. 
Mode of Transmission. —This is effected by Argas 
miniatus. This tick is a night feeder. A temperature 
of about 35 0 C. is necessary for successful transmission. 
The ticks remain infective for one month after feeding. 
To Stain Spirochaetes in Sections. —Levaditi and 
Manoulian* give the following as their latest formula. 
1. Fix small pieces of tissue, I millimetre thick, 
in formalin. Harden in ninety-five per cent, alcohol 
one hour. Then into distilled water until they sink. 
2. Put into a solution of one per cent, tannin to 
which enough pyridin is added to clear up the turbidity 
arising on first mixing. Keep in this for one-quarter 
hour at 50° C. 
3. Wash several times in distilled water. 
4. Place in a solution of silver nitrate 1 per cent., 
to which is added some pyridine ten per cent. Keep 
at 50° C. for one-quarter hour. 
5. Wash. Reduce with four per cent, pyrogallic 
acid, to which is added enough pyridine to make the 
mixture clear. Reduction takes place in a few minutes. 
6. Wash, alcohol, xylol, paraffin. Cut sections. 
7. Double stain with neutral red and methyl 
blue. 
10. Sp. vespertilionis. —In a Tunisian bat, V. kuhli. 
The infection is sometimes fatal, and relapses occur. 
The incubation period, after inoculation, is about 
forty-eight hours. The spirochaete is 12-18^. They 
disappear out of the blood by crisis. 
The spirochaete, according to Gonder, divides 
An. de VInst. Pasteur , p. 297, 1907. 
