684. MURIEL ROBERTSON. 
dry —or they were plunged while still wet into corrosive sub- 
limate and acetic acid and treated by wet methods through- 
out. It is a matter of regret to me that I did not fix more 
material in this last way. The films were stained by various 
Romanowsky methods, or, in the case of wet films, in Heiden- 
hain’s iron hematoxylin or Khrlich’s heematoxylin.! The Try- 
panosome was also studied in section from the various organs. 
The drying method followed by the Romanowsky stain 
gives excellent results with certain types of object, but may 
at times give misleading pictures, more especially with more 
massive creatures. It is therefore advisable, where possible, 
to control the results with material treated by wet fixation ; 
osmic films are very valuable, but are open to the same 
objection in the matter of drying. he drying method seems 
to flatten and spread out certain types of organism; on the 
other hand, the wet fixation of blood-films equally certainly 
causes the parasite to shrink. ‘his is very marked in certain 
Hemogregarine phases. Fixation is generally a choice of 
errors, but by the combination of the dry and the wet method 
a very fairly accurate idea of the nuclear structure of the 
organism may be obtained. 
Trypanosoma vittate (Pl. 16, figs. 1—7) in the blood 
of the vertebrate host shows dense protoplasm, markedly 
alveolar with longitudinal striations, corresponding to the 
myonemata so clearly visible in the live state. ‘hese are not 
always equally conspicuous. There is no doubt that the adult 
‘'vypanosome in the blood of the vertebrate is possessed of 
quite a definite outer sheath or periplast—this is clearly 
visible in crushed specimens. ‘lhe myonemata appear to 
form part of this structure. 
The protoplasm has a tendency to stain deeply, whatever 
the method used; granules and protoplasmic inclusions are 
never, in my experience, visible at this stage in the stained 
preparations. In the live state there are sometimes bright 
globules to be seen in the protoplasm; they are not very 
! Tam indebted to Prof. Minchin for advice on the handling of these 
wet preparations, 
