774 E, A. MINCHIN. 
much larger after the Romanowsky stain than it does after 
iron-hematoxylin, perhaps four times as large; the same two 
types of form are to be made ont in the kinetonucleus, but 
they have become magnified, as it were, in the former case. 
The trophonucleus is not only much larger after staining by 
the Romanowsky method, but its structure appears quite 
different from that seen after iron-hematoxylin and other 
methods. In the place of a simple oval vesicle-like structure 
containing a deeply staining karyosome, we find after the 
Romanowsky stain an opaque mass of deeply stained coarse 
grains of reddish colour, in which a karyosome often cannot 
be made out with certainty, Sometimes the stained grains 
are closely packed and scarcely distinguishable individually ; 
sometimes, and especially in preparations dried before fixa- 
tion, the grains appear separate and distinct, Very fre- 
quently the nucleus shows a clearer spot at or near the centre 
(figs. 70, 80, 81). The flagellum appears thick and coarse and 
the blepharoplast is usually fairly large and distinct after the 
Romanowsky stain. 
What is the explanation of these differences? The large 
size of the kinetonucleus and trophonucleus and the thick- 
ness of the flagellum after the Romanowsky stain are shown 
by the standard (figs. 1-8) to be a case of actual enlargement 
or thickening, not to be explained by supposing that after 
other methods, such as the iron-hematoxylin stain, these 
structures are shrunk. Such an enlargement can only be 
explained by a tendency of the red stain cr stains, which are 
active in the Romanowsky combination, to deposit not only in, 
but also around, the structures that are coloured by them. 
Comparison of the kinetonucleus, in preparations stained by 
the Romanowsky method and by other methods, is alone 
sufficient to prove conclusively that the enlargement is due to 
this cause, and gives a clue to the interpretation of the very 
remarkable and perplexing differences seen in the structure 
and appearance of the trophonuclei in the two cases. 
In order to discuss the effects of the Romanowsky stain on 
the trophonucleus, it is necessary that I should anticipate here 
