1908.] The Infe-history of Trypanosoma equiperdum. 291 
typical malarial infection. In the case of 7. gambiense it has been found* 
that amitotic division of the parasites proceeds up to the first maximum, but 
at this period other changes are also apparent in the parasites of the blood 
(see Diagram I, a, 6, c.) At this period numbers of parasites may be found in 
Diagram I.—Showing the cyclical metamorphosis occurring in Trypanosoma gambiense in the 
blood from an infected rat. a. The longitudinal fission of the parasites. 6. The interaction 
between the extra-nuclear centrosome and the‘nucleus. c. The formation of the latent 
bodies and the early stages of their redevelopment into trypanosomes. 
which a thick band is seen to be growing out from the extra-nuclear centro- 
somes (blepharoplast) which lies about the base of the flagellum (Diagram I, 0). 
This band extends down the interior of the body towards the nucleus. After 
a time the band enters into connection with the nucleus, and then breaks up 
and disappears.— At or near the maxima there is thus an interaction between 
the extra-nuclear centrosome and the nucleus. When the maximum has 
* Salvin Moore and Breinl, loc. cit. _ 
+ Referring to our communication, ‘ Annals of Tropical Medicine and Parasitology,’ loc. 
cit., Swellengrebel (‘Compt. Rend. Soc. Biol., vol. 64, 1908, No. 2) appears to regard the 
formation of the stainable band as in some manner due to a form of degeneration. We 
are, however, entirely unable to agree to this conception for the following reasons. The 
formation of the band occurs only at a particular period of the infections, and at other 
periods it is not induced either by the administration of substances such as atoxyl or by 
allowing the trypanosomes to die. A clearer demonstration of the erroneous conclusion 
drawn by Swellengrebel is, however, found in the facts relating to 7. equiperdum ; 
here a similar process regularly occurs (see this paper) and after it has occurred the 
trypanosomes again pass through division, this fact demonstrating that the process to 
which we refer can have nothing to do with degeneration and is, on the contrary, part of a 
cycle occurring during the ordinary course of development. 
Swellengrebel appears to us to be again in error in supposing that the formation of 
the stainable band is connected with the production of trophic granules. That this is not 
the case can readily be seen by the use of stains such as that of Breinl or modifications of 
the iron hematoxylin method, whereby the remains of the band and the band itself 
stain quite differently to the trophic granules. Moreover, before any stainable band is 
produced the trophic granules are numerous and must have arisen from some other 
source. 
