228 Trypanosoma lewisi 
Art fuhren meist zu Verklumpungsfiguren der basichromatischen Granula 
und liefern dabei homogene Farbung der grosseren Teile der Gertistwerke 
und der Chromosomen.” In view of this statement it is not astonishing 
when the karyosome in the nucleus of Tr. leivisi is so intensely stained 
with iron-hematoxylin, whereas the surrounding parts of the nucleus are 
stained a pale-grey colour without any structure. 
While studying the literature on Tr. lewisi it was necessary to know 
exactly the value of the methods of dry fixation and Giemsa’s staining, 
to be able to judge some of the recent papers on this subject. This 
knowledge was absolutely necessary, especially because Minchin says of 
Prowazek’s work: “ Moreover Prowazek seems to have based all this 
theoretical superstructure upon Romanowsky-stained preparations, which 
in my opinion are altogether false and misleading for minute nuclear 
structure.” 
In this note I will not try to interpret any nuclear or protoplasmatic 
structure observed. They are only considered as an indicator of the 
value of the different methods of fixing and staining. 
Fig. 1. Standard preparations. Fixation in osmic acid vapour. Unstained. 
Standard preparations after Minchin’s method were made but not 
with the same favourable result. I often observed a notable deformation 
during the fixation in osmic acid vapour. To exclude as perfectly as 
possible all causes of error, the standard preparations were not coloured, 
as was done by Minchin. Except for the general form my observations 
correspond with Minchin’s (Text Fig. 1). The blepharoplast is round or 
oval shaped. Sometimes I was able to detect within it a peculiar 
structure. It seemed then to consist of two highly refractive granules, 
united by a less refractive substance (Fig. lo and lc). Generally it was 
