423 
DEGENERATION PHENOMENA OF 
TRYPANOSOMA GAMBIENSE. 
By EDWARD KINDLE, Ph.D., A.R.O.S., 
Beit Memorial Research Fellow. 
{From the Quick Laborato7'y, Cambridge.) 
(With Plate XXX.) 
In spite of the numerous papers that have been devoted to a 
consideration of the morphology of Trypanosoma gambiense, our 
knowledge of the life-history of this parasite, both in the vertebrate 
and invertebrate hosts, is very incomplete. One of the reasons for 
this is undoubtedly the practical difficulty of studying the parasite 
in its natural surroundings, and in its normal vertebrate host, man, 
and up to the present most workers on this subject have confined their 
attention to the morphology of this trypanosome when under somewhat 
unnatural conditions, for none of the ordinary experimental animals 
(rats, guinea-pigs, etc.) in which it is studied, are known to be 
susceptible to natural infection. Therefore, any results obtained from 
such studies of the parasite must be regarded as indicating only what 
probably takes place under natural conditions, and, as such, remain 
sub judice until confirmed by observations in the normal hosts. 
Although white rats, the animals used for the following observations, 
are not known to be susceptible to natural infection with T. gambiense, 
yet it is evident, from the well-marked periodicity in the number of 
parasites in the peripheral circulation, that some kind of life-cycle takes 
place in this host. In attempting to follow this cycle it was found 
