1904.] the Trypanosomata of Gambia Fever, etc. 389 



paralysed in both hind legs on May 12, 1904, and died on May 23 ; 

 the second became paralysed similarly on August 2, and died on 

 August 30 ; and the third became paralysed on August 28, and died 

 on September 8. On post mortem examination no naked-eye lesions of 

 any organ were found, and the spleens were not enlarged. The blood 

 was citrated and centrifugalised, and the organs were mashed and 

 washed with normal salt solution and centrifugalised, but in no case 

 were any Trypanosomata found. Portions of the extracts of liver, 

 spleen, and spinal cord were injected into other rats, but up to the 

 present these show no sign of illness. In the mashed spinal cord of 

 each of these rats the characteristic Trypanosomata were found in 

 small numbers, but none were found in the brains which were examined 

 in the same way. The three rats were of the same kind, black and 

 white ; and the youngest of the three died first and the eldest last. 



(1) These experiments go to show that the two diseases Gambia 

 Fever and Sleeping Sickness from which the organisms were obtained, 

 are distinct; the duration of the diseases, the symptoms, and the 

 post mortem appearances being quite different. 



It is evident that these two organisms are quite separate and distinct, 

 as their different effects on similar animals indicates ; moreover, they 

 are also morphologically distinct when grown in similar animals, that 

 of Gambia Fever being longer, generally larger, and more easily 

 stainable than the stumpy, large-vacuoled, badly staining Trypanosoma 

 of Sleeping Sickness. 



The fact of the clinical observation that Gambia Fever not infre- 

 quently appears to terminate with all the symptoms of Sleeping 

 Sickness may quite possibly be explained by a double infection. For, 

 in both rats and monkeys the one Trypanosoma does not interfere 

 with the other, but the more active organism that of Gambia Fever in 

 the cases of rats and monkeys kills in about the same time, whether 

 inoculated before, with, or after that of Sleeping Sickness. 



(2) There can be no question, from the above experiments, of the 

 susceptibility of the rat to the Trypanosoma of Sleeping Sickness. 



(3) These experiments show that the inoculation of the Trypano- 

 soma of Sleeping Sickness into rats gives rise to no obvious symptoms 

 for many months, nor are Trypanosomata discoverable in the blood by 

 microscopic examination. But, after a period of from six to nine months 

 paraplegia occurs, leading to the death of the animal ; and post mortem 

 the organisms are found only in the spinal cord. The organisms are 

 thus in rats, as sometimes in man, entirely confined to the nervous system; 

 whereas in monkeys they are, in my experience, always generalised at 

 some period of the disease. 



