306 
PROFESSOR ARTHUR ROBINSON ON 
The ovaries of opposite sides were, as a rule, placed in different fluids, and the 
fluid used in the case of each ovary is stated in the appended tables. 
The post-fixation processes were those in ordinary use in association with the 
fixatives used, and in all cases in which the fixative fluid contained mercuric per- 
chloride the mercury salt was removed by iodine in 75 per cent, alcohol. 
Embedding and Staining. 
All the ovaries were embedded in paraffin after being passed through alcohol in 
increasing strength, into alcohol and xylol, xylol, xylol and paraffin, and finally pure 
paraffin melting at 55 '5° C. 
Some of the ovaries were stained in bulk in Meyer’s haemalum before being 
embedded. This method cannot be recommended, in spite of the fact that it gives 
beautiful differentiation, because it is apt to shrink and hardeji the fibrous stroma of 
the ovary to too great an extent. 
The majority of the ovaries, which were not stained in bulk with hsemalum, were 
faintly stained with eosin, placed in the various alcohols through which they were 
passed. This facilitates the selection of the sections, which are to be treated by 
various staining methods, before the paraffin is removed from them. The stain is, 
in most cases, completely washed out in the subsequent processes. 
The majority of the sections were cut 10 /r thick, some were 7/y still fewer 5ja, 
for I found it practically impossible to get a satisfactory series of sections of 5/r. 
The sections were fixed to the slides with egg albumen. 
Most of the sections of the various ovaries were stained by Heidenhain’s. iron- 
hsematoxylin method, sometimes in the ordinary way, but more frequently, and with 
better results, with the modification suggested by Rubaschkin (33) — that is, the 
sections were placed for one minute in a ‘25 per cent, solution of potassium perman- 
ganate, washed in water, placed for one minute in a solution containing '5 per cent, 
of potassium sulphite and ‘5 per cent, of oxalic acid, and then washed for one hour in 
running water before they were mordanted in iron alum. 
After the iron-hsematoxylin process was completed some of the sections were 
mounted without further treatment ; others were counter-stained with anilin blue, 
with orange green, or with a mixture of the two ; with eosin, or with light green, or 
with erythrosin and light green. 
Other sections, not treated by the iron-hsematoxylin process, were stained with 
erythrosin and light green, with Mallory’s connective-tissue stain, with safranin 
and light green. 
Special sections were selected for treatment with the various elastic-tissue 
stains, and others, for the demonstration of mitochondria, by Meves’ and Benda’s 
methods. 
