308 
FREDA RAGE. 
had been preserved in Flemming's solution, and two of these 
were cut. They gave very good results so far as the shape 
of the visual cells is concerned. There was apparently little 
or no slirinkag*e, but I find that sections of material fixed in 
this way do not stain readily, owing, of course, to the osmic 
acid employed. The most useful results with this material 
Avere obtained by staining in bulk Avith borax carmine, and 
on the slide Avith brazilin. There is very little differentiation 
in colour by this method, the sections being of a brownish 
tint for the most part; but the nuclei throughout are Avell 
marked, their chromatin showing most distinctly, and the 
paraboloids of the sense-cells staining Avith a slight pink 
tinge in contrast Avith the rest of the sections. The oil- 
globules are, of course, quite black, owing to the osmic acid, 
and the outer segments sIioav good detailed structure and are 
not much broken, though somewhat shrivelled. 
Iron-liasmatoxylin gives fair results, the nuclei being Avell 
stained and of a bluish tinge, but the different parts of the 
sense-cells are not Avell differentiated. 
On some of this material, AAdiich had not been previously 
stained in bulk, I tried a ready-made “ Weigert Pal" stain 
obtained from Grubler. It Avas not possible to subject the 
already hardened and preserved material to all the pre- 
liminary processes which form a part of this method, and the 
sections obtained, though they Avere useful, were practically 
unstained, and resembled those cut and mounted Avithout any 
staining on the slide, being of a yelloAvish tinge with black 
oil-globules and outer segments. I made use of them, 
however, because the nerve-fibrils of the various cells, though 
unstained, Avere unusually distinct. 
(b) Zenker Material. — The paired eyes of Spheno- 
don III, Avhich had been fixed in Zenker's fluid, were 
excellent for the general histology and cytology of the 
sense-cells. The eyes Avere stained in bulk Avith borax 
carmine and various other stains Avere used on the slide. 
Picro-indigo-carmine gave excellent results, differentiating 
the various layers and cells in shades of green and red. The 
