766 KE. A. MINCHIN. 
to stand out distinctly from the body (see below). By the 
never-dried method, however, a periplast-line appears very 
distinctly in the iron-hematoxylin preparations (Pl. 21, figs. 
10, 11). Its appearance in the preparations stained with the 
Romanowsky stain depends largely on the degree to which 
the stain has been extracted by the acetone during the 
process of mounting in Cauada-balsam, and the result varies 
greatly in one and the same slide (Pl. 22, figs. 64-69) ; -a 
matter which I shall discuss more fully in the section dealing 
with this stain and its effects. One of the most constant 
results of the process of drying off is seen in the relations of 
flagellum, blepharoplast and kinetonucleus. In never-dried 
preparations the flagellum starts from close to the kineto- 
nucleus, with which the blepharoplast is nearly in contact. 
In dried-off preparations, on the other hand, there is a 
distinct interval between blepharoplast and kinetonucleus, 
almost equal to the width of the latter in many cases (PI. 22, 
figs. 60, 61). ‘The same result is seen in preparations in 
which osmic fixation is followed by Flemming’s fluid or other 
reagents, and dried off after staining with Romanowsky’s 
stain, and also in preparations dried before fixation. it 
follows, therefore, that the effect of drying is to draw apart 
kinetonucleus and blepharoplast, probably as the result of a 
longitudinal contraction in the flagellum or in its basal portion. 
(2) Osmice acid mixtures.—The two famous combina- 
tions, Flemming’s fluid and Hermann’s fluid, were used, the 
former both direct on the wet film and after previous exposure 
to osmic vapour, the latter only directly on the film. ‘he 
Flemming’s fluid used was the so-called strong mixture; the 
Hermann’s fluid was made up in the same manner, and 
differed only in the substitution of platinum chloride (so-called), 
1 per cent., for the chromic acid, 1 per cent. A variety of 
staining methods was tried on these films; I will describe the 
results obtained by the various stains in the sections dealing 
specially with them below. The best results were obtained 
with iron-hematoxylin, and the following account of the 
action of these two fixatives refers more particularly to 
