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FIXATION AND STAININOx OF TRYPANOSOMA 
LEWISI. 
By Dr N. H. SWELLENGREBEL, 
Privat-docent in the University of Amsterdam. 
{From the Hygienic Inst., University of Amsterdam. 
Director : Prof. Dr R. H. Saltet.) 
7 Text Figures. 
Since the publication of Moore and Breinl’s paper (1908) a new 
method of wet fixation has been introduced into the technique of 
protozoological research. It is generally stated that the old method of 
drying the blood films and fixing them afterwards in absolute alcohol, 
destroys the minute details of nuclear and protoplasmatic structure; 
that the preparations made in this way are wholly misleading and the 
structures do not correspond to those of the living Trypanosomes. This 
becomes evident when we compare the figures of Moore and Breinl 
and of Rosenbusch (1909), who studied Tr. lewisi with the aid of 
wet fixation in Flemming’s liquid, with those of other authors (Prowazek 
(1905), Wenyon (1908) etc.) who studied the same subject. The 
structure of the nucleus is very dissimilar with the two methods. The 
big karyosome observed by the first authors cannot be found with dry 
fixation; then only one or more minute granules are to be seen. 
If this old method of investigating Trypanosomes and other 
hematozoa is really nob to be trusted, many of the recent papers on 
the cytology of Trypanosomes {e.g. Prowazek’s work) are valueless 
whenever minute cytological details are considered. Before reaching 
this conclusion it will be useful, however, to compare the different 
methods of wet and dry fixation and to make sure if this old method is 
really so bad as many authors assert it to be. 
