566 
MARGARET ROBINSON. 
by Heidenliaiu’s method. Following the directions given by 
Brasil (1905), I left them for twenty-fonr hours in the 
mordant, and for thirty-six or more in the hyematoxylin. As 
plasma stains after Heidenhain I used a mixture of Licht- 
Gri'm and picric acid in equal parts dissolved in absolute 
alcohol, orange G., and eosin. 
Two other stains of which I made use were Delaheld’s 
hfematoxylin and that of Kleinenberg. 
The First Spindle. 
The nuclear membrane disappears gradually bit by bit, 
and the nucleus becomes more or less diffuse, assumino- an 
irregular outline in the parts no longer contained by the 
membrane. Close to this uneven edge there appears a little 
cluster of rod-like pieces of very darkly staining chromatin. 
'I'liese small rods are connected together by a tine thread, 
which stains more faintly than they do, so as to form a small, 
loosely folded skein. Part of this skein rests on the achro- 
matic fibres of the spindle. These fibres are doubtless intra- 
nuclear in origin. The spindle has centrioles which stain 
deeply with Heidenhain’s haematoxylin ; and there are the 
usual terminal radiations in the cytoplasm (fig. 1). 
In my next stage, which follows very closely upon the 
above, the nucleus is almost completely dissolved, all that 
remains of it being two or three karyosomes still uuabsorbed 
by the cytoplasm. The spindle is now in anaphase (fig. 2). 
It shows a good number of deflected radiations, in this much 
resembling one figured by Brasil (1905), but hei’e one can 
see a well-marked centrosome. I could not demonstrate a 
centriole. 'Hie number of the chromosomes is four. In 
metaphase (fig. 3) it is impossible to count the clu'omosomes, 
and there appear to be more than four, but in the anaphase 
they can generally be counted, and as I have seen numbers of 
nuclei in this phase I am in no doubt as to the number. 
This appearance of the first spindle agrees in all essentials 
with the events described by Cuenot (1900), Brasil and 
