THE NATURE OF HUMAN TICK-FEVER 
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marrow was diffluent and chocolate coloured. Heart, kidney, and liver seemed cloudy. 
Spleen, enlarged, measured 7 by 2.8 by 1.7cm. ; firm. No malarial parasites, trypano- 
somata, or filariae were seen in this animal. 
Ex. 160: Young- Cercopithecus, weight 1,586 grammes. 
Ticks caught in native houses at Nyangwe were, on Nov. 24, fed upon a small 
rabbit (Ex. 154), whose blood contained main- spirochaetes. On Nov. 30 twenty-six of 
these ticks fed upon this monkey. On the morning of Dec. 5 spirochaetes were for the 
first time seen in its blood. The par?S'tes became more numerous, and were constantly 
present. On Dec. 10 the temperature w as sub-normal, and the animal dying. It was, 
therefore, killed to obtain blood for inoculating exps. 155, 1 50. 163. No malarial 
parasites, Trypanosomata, or filariae were ever seen in this monkey. 
Ex. 167 : Young Cercopithecus, weight 906 grammes. 
Dec. 21 and 22. — One hundred and seventeen ticks caught in native houses at 
Nyangwe before Nov. 23, and not since fed, were allowed to feed upon this monkey. On 
Dec. 28 spirochaetes were seen in the blood for the first time, and the temperature rose. 
Parasites were constantly present, at first in large numbers, until Jan. 10. From that 
date until death on Jan. 19 parasites were absent from the peripheral blood — examined 
both during the day and at night. During the last few days the animal was extremely 
weak, hardly able to crawl, and had slight diarrhoea. The autopsy was commenced 
immediately after death. The animal was very thin, weight 604 grammes, all fat had 
disappeared. Spleen was slightly enlarged, 3.25 by 1.75cm., dark and firm. All other 
organs were extremely ansemic. Long bone-marrow dark red. A few spirochaetes were 
seen in preparations of heart blood, bone-marrow, and spleen juice taken at the autopsy. 
No malarial parasites, trypanosomata, or filariae were ever seen in this animal. 
Ex. 176: Young Cercopithecus, weight 1,020 grammes. 
On Jan. 12 and 13 258 ticks caught at Nyangwe, before Nov. 23, and not since fed, 
were allowed to feed upon this monkey. On Jan. 16, 76, and on Jan. ig, 240 of the same 
ticks were re-fed. On Jan. 21 spirochaetes in fair numbers, were seen in the blood for 
the first time. The animal died on Jan. 23. Death was largely due to rough handling 
while feeding further batches of ticks. Spleen was slightly enlarged, 4.75 by 3cm., dark 
and firm. This monkey was infected with malaria, but neither filariae nor trypanosomata 
were seen in its blood. 
Ex. 184: Adult Cercopithecus, weight 2,380 grammes. 
On January 23, the ticks which had infected Ex. 160 on Nov. 30, and had since 
repeatedly fed on uninfected animals, were placed on this monkey; thirteen fed. On 
Jan. 28, Feb. 1, 2,, and 6, they had again opportunities of feeding-, the monkey being 
bitten fifty-nine times. On Feb. 6 another lot of infected ticks were accidentally placed 
on this animal for a few minutes. Three or four may have punctured the skin, none 
fed. On Feb. 14 and 18 the monkey was bitten twenty-three times by the first lot of 
ticks. On Feb. 19 spirochaetes were seen in the blood for the first time, and the tem- 
perature rose. Parasites were fairly constantly present in the peripheral blood until 
March 7. Since then they have been absent, though the temperature remains high. The 
animal is still under observation. * 
Ex. 192 (Chart 9) : Young Cercopithecus, weight 1,020 grammes. 
It was thought possible that "J. L. T." might have become infected with spirilla 
through his unprotected hands while rising the autopsy on Case 4. To ascertain whether 
a susceptible animal would become infecter 1 w ; th spirochaetes if parasite-containing blood 
were placed on its unbroken skin, the haii was carefully clipped from the abdomen of 
this monkey, a healthy area was chosen, and, after a careful negative examination — 
with a lens — for cuts and abrasions, a few drops of blood containing many spirochaetes — 
from Exps. 162 and 163 — were placed upon the unbroken skin. The blood was covered 
with a damp chamber to prevent its drying, and was removed after thirty minutes. This 
was done on Dec. 13, 15, and 17. The blood was examined daily until Dec. 27. As no 
parasites were seen, the animal was thought to be uninfected, and it was decided to use 
it for a second experiment. 
* October 23rd, 1905. Temperature constantly elevated (malaria). Blood frequently examined; no 
spirochaetes been until May 13th, 1905 (T. 107.2) one to field. None were again seen, though blood was 
constantly examined, and on August 23rd the animal died in convulsions (no spirochaetes found at autopsy;. 
V Cause of death, slight broncho-pneumonia. 
