456 DR THOMAS H. BRYCE ON 
general way, to identify the elements in a series stained with this dye and counter- 
stained with eosin. 
On a new series I tried many stains, but owing to some factor in the fixative, 
presumably the acid, I found the tissue would not stain with any basic dye. I had 
recourse, therefore, to Mann’s double acid mixture of methyl blue and eosin, but 
found that for this particular material I got much more vivid differentiation by staining 
with the two dyes successively, first for three minutes in a saturated watery solution of 
eosin, and then, after rising in water, in a saturated watery solution of methyl blue 
for one or two minutes. The results varied according to the proportion in which the 
two dyes were held; and although there was some variation in the colorisation, the 
conclusions were not vitiated, because the picture was always a relative one. 
The general effect depended partly on a difference in the reaction of the protoplasm, 
but chiefly on the relative proportions in the nuclei of bodies with different affinities 
to the two dyes. 
In my most successful stainings I obtained the following results :— 
A. Fixed Cells. 
The protoplasmic trabeculze stain pure blue, and the nuclei have a general blue tint 
owing to the general reticulum of the nucleus selecting the blue dye, but the nucleoli 
(chromatin) stain a violet-red colour. The central parts of the karyosomes stain 
yellowish-red. The violet colour is given by an outer covering or coating, as it were, of 
the blue staining general linin reticulum. 
B. Free Cells. 
1. In the meshes of the trabeculee there are large numbers of cells with a large 
nucleus and a small amount of blue-staiming protoplasm. The nuclei are round and 
vary In size, but roughly they may be divided into two classes—those with a diameter 
about 24 » and those with a diameter of about 18 u Many have smaller nuclei, 
but as there are frequent mitoses they may be considered young cells. The nuclei 
are characterised (fig. 33, Pl. IV.) by the large amount of blue they select, the general 
fine reticulum taking up the methyl blue, while the chromatin nucleoli, which are 
relatively few in number, stain reddish-violet. The characters are thus exactly the 
same as the nuclei of the reticulum. 
2. Distinguished from these cells are others which have nuclei of the same dimen- 
sions as the largest of the cells of the last category, but which react differently to the 
stain (fig. 33, Pl. IV.), their general tint being reddish-violet. This is due to a difference 
in the disposition of the chromatin. The nucleoli are larger and are more closely opposed, 
and the blue-staining reticulum between them is reduced, and has a violet, not a pure 
blue tint. These cells are very frequently seen dividing, and are distinguished during 
division by the red-violet colour of their chromosomes. The daughter cells have 
