THE NATURE OF HUMAN TICK-FEVER 
119 
The disease was most probably contracted at the autopsy done on Case 
4, at Nyangwe, on November 19 : after the autopsy was finished a slight 
abrasion was noted at the side of one of the finger nails. If such is the 
case the incubation period was, as usual (8), seven days. Though there is 
no knowledge of a tick-bite, the possibility of infection by that means cannot 
be definitely excluded, since on arriving at Kasongo ticks — two — were found 
in an unopened valise and in a bed-covering in daily use ; and this although 
no ticks were seen in the rooms we had occupied in a few days before at 
Nyangwe. 
The second European case was much the less severe. The symptoms — 
head and boneache, lassitude, slight nausea and diarrhoea, scanty febrile 
urine during and increasing micturition after the attack, tenderness over the 
imenlarged spleen, and fever noted in the first case were all present in the 
second, but with greatly lessened intensity. 
The diary of the case is as follows : — 
J. L. T. {Chart No. 7). (Patient's Own Notes.) 
Dec. 3 and 4. — Felt vaguely unwell. Quinine 7} grains each day. 
Dec. 5 and 6. — Quite ill ; blood examined, spirochaetes present — no malarial para- 
sites seen. 
Dec. 7 to 17. — Felt perfectly well. Quinine grs. 5 taken on Dec. 8 and 9. 
Dec. liX. — Only slight malaise; small epistaxis during- night. Blood net examined. 
Dec. iq to 31. — Well. 
Jan. 1. — Passed a bad night; head and backache annoying,. For three or four 
succeeding days was much troubled with neuralgia (patient not neuralgic). Blood 
examined, spirochaetes present. 
Jan. 5 to 15. — Well. 
Jan. 13. — Passed an uneasy night, slight diarrhoea. 
Jan. 14. — Usual symptoms; great feeling of weakness. 
Jan. 15 to present. — Patient free from symptoms, and entirely well. No malarial 
parasites were seen during the whole of this illness. 
The Disease in Experimental Animals. 
As the following abstracts of experiments indicate, the spirochaete does 
not kill the ordinary laboratory animals. To monkeys alone, the C ' crcofit heci , 
especially young animals, does it seem uniformly pathogenic. An adult 
rabbit (Ex. 156) was refractile. A young rabbit (Ex. 154) and a rat (Ex. 
162), in whom there were grave accompanying affections, seemed more 
susceptible. A large guinea pig (Ex. 155) showed spirochaetes in its blood for 
only two days succeeding the inoculation of a large dose of heavily infected 
blood. In it, as 111 three rats (Ex. 163, 166, and 185), from whose blood 
spirochaetes, once present, finally disappeared, there appears to have been a 
temporary increase in the number of the parasites, and dividing forms were 
seen. 
RABBITS. 
Ex. 154; Rabbit, about one month old, weight 675 grammes. 
Nov. 15. — Inoculated with about 5cm. blood from Case 4, showing two spiiochaetes 
to held. 
Nov. 16 to 17. — Scanty parasites present in blood. No spirochaetes were then seen until 
Nov. 24 and 25, when there were about twenty to a field (i-i2th oil immersion objective; 
No. 4, ocular; Zeiss). In spite of daily examination no parasites were again seen. The 
animal died in convulsions on Jan. 23. The probable immediate cause of death was a 
very severe skin disease ( ?). 
