170 
E. A. M INCHIN AND H. M. WOODCOCK. 
apparently composed of coarser, more closely packed granules. 
It was stated then that these bands were not to be regarded 
as actually representing myonemes. Now, in the case of the 
large blue trypanosomes from the little owl, most of the well- 
fixed individuals, i.e. those most closely approximating in 
form (shape) to the corresponding type on wet films, show 
scarcely any indications of such a structural differentiation of 
the cytoplasm. Only in one or two individuals, which are 
relatively rather wide, can traces of the bands be made out 
(cr. fig*. 11). And none of these forms on wet films shows 
any signs of this peculiarity, the cytoplasm being practically 
homogeneous; this fact is, we think, most instructive. We 
have come to the conclusion that this appearance is, to a large 
extent, artificial, and chiefly the result of a certain flattening- 
out on the “ dry ” Giemsa-stained smears. The narrower and 
more compact the general cytoplasm of the parasite, the less 
conspicuous is this band-like arrangement. 
It may be asked, Why was this condition found very fre- 
quently in the large forms of T. f ringillinar um, which 
were figured as normal ? It must be recalled in explanation 
that the preparations on which tlie account of these forms in 
the latter trypanosome was based differed in two respects 
from those we have of the parasites from the little owl. In 
the first place, no wet films of T. f ri n gill in arum were 
obtained. Secondly, the smears were made from the peri- 
pheral blood, and Avere, of course, evenly spread out and thin. 
On the other hand, in the case of the trypanosome Avith. which. 
Ave are now concerned, all our preparations shoAving these 
large individuals are made from the bone-marroAV, and the 
smears are not nearly so thinly spread out. In fact, the best 
fixed examples of these large forms are those which occur in 
the neighbourhood of clumps and masses of cells. 
It is fairly certain, therefore, that in the blood-smears con- 
taining T. f ri ngi llin arum, these large blue parasites Avere, 
Avhile really not distorted, nevertheless sufficiently flattened- 
out to produce this effect of bands in the cytoplasm. At the 
time, however, there Avas no reason Avhy one should have con- 
