454 
four nuclei, without, however, the extra-nuclear centrosome having 
divided more than once. Or the extra-nuclear centrosome may 
divide and form three or four flagella without the nucleus having 
divided at all. When these unusu.il methods are adopted, the 
gigantic trypanosomes figured on Plate 1 are frequently produced. 
Changes in the Trypanosomes relative to the Stage of Injection 
The appearances described in the preceding paragraphs are those 
which are encountered among the parasites during multiplication after 
their first appearance in the blood of the infected animal, h 
however, other stages of the infection be studied there are to be 
found different morphological appearances among the parasites, which 
are apparently of the greatest importance. In the case of an amm 
which has become infected with Trypanosoma gambiense, and sho*» 
a well-marked oscillation in the course ol the disease, it is found t a 
as the number of the parasites is rising in the blood —-that * s t0 ^ 
along the ascending portions of the curve in the diagram 
(page 4 i! ia i 
the phenomena presented are the same as those found in the inu ^ 
stages of the infection which we have just described. If, h°' ve ' er ^ 
study preparations made at or near the maxima of the curve ^ 
changes are found to be taking place in the trypanosomes 
those of simple division. ^ ^ 
At the time the curve approaches any maximum, there are ^ 
found trypanosomes which present the appearance shown m & ^ 
to 20. From this figure it will be seen that such trypaH 0 ^ 10 ^ 3 
distinct from those which have been previously described, in 
relatively-thick stainable band proceeds from the extra-nu c * ear j r0ll 
some. This thick band is found to be most readily staina ble 
haematoxylin ; it is less readily, but still stainable by the ' tra - 
aniline colours which we have employed. It grows from the ci5 e 
nuclear centrosome not along the surface of the animal as in 1 
of the new flagella, but down the interior of the cell to** r ^ 
nucleus (see figs. 15, i6). v This stainable band, which apP^ 
* It is probable that the band we here refer to is the same a* tb d- ^ 
described by Prowazek Studien uber Saugeth.er trypanosomen. .\rb- 3 o0 cegft, 
C ’ Band XXII A *905. and also Miss Robinson, Vol- N 
blood-inhabiting protozoa. Proceedings of the Royal Society, 
