118 E. A. I\IINCniN AXI) H. M. WODTiCOCK. 



at tlie same time. Here the average is only 4'2/u by 2'2 /ii 

 (cf. figs. 58, 60, 61). We are rather at a loss to account for 

 this case, but it seems evident that shrinkage must liave 

 taken place sojnetime during the manipulation. 



In the small type of the parasite the nucleus is relatively 

 large. As already mentioned, it is genei'all}'' situated entirely 

 in one half of the body and near one end, but now and then 

 it occupies a more median position (fig. 5). In Giemsa-stained 

 preparations the nucleus appears to take up quite half the 

 body, or even more, and to occupy its entire width or even to 

 bulge out slightl}' at the sides (figs. 1, 2, 7). From prepara- 

 tions stained with iron-htematoxylin, howevei-, it is apparent 

 (cf. figs. 39-45) that in the former smears there is a certain 

 amount of artificial enlargement, due to the characteristic 

 overloading with the stain which so detracts from tlie value 

 of the Romauowsky method. We reserve a detailed descrip- 

 tion of the structure of the nucleus until later, when we 

 com])are it with that of a trypanosome. The general cyto- 

 plasm appeal's fairly homogeneous in character, and with the 

 exceptions to be mentioned, is usualh- devoid of granules. A 

 conspicuous vacuole is frequently present; this lies about the 

 middle of the body, generally close to the nucleus. In 

 Giemsa smears it is sharply defined, because the cytoplasm, 

 as a rule, is distinctly stained, eithei" purplish or bluish in tint 

 (figs. 1, 8, 16, 17) ; but in irou-ha?matoxylin preparations it 

 is often difficult to make out, probably owing to the fact that 

 the cytoplasm of the parasites in these smears is itself very 

 pale and scarcely stained at all ; sometimes, however, it is 

 well seen (fig. 40). Rarely the cytoplasm contains two or 

 three vacuole-like areas, Avith less sharph' defined limits (cf. 

 figs. 2,41). 



The most striking feature in the morphology of the para- 

 sites, as brought out by iron-ha?niatoxylin, is afforded by one 

 or two large granules, Avhich take up this stain with intense 

 avidity (cf. figs. 39, 40, 43, 46). They are often present, but 

 not always (figs. 41,42). When they occur these granules 

 are by far the most prominent objects in the body, appearing 



