242 
NOTES AND MEMORANDA. 
ance, an answer to the question How do the nucleated red 
corpuscles of the red bone-marrow give rise to the non-nucleated 
red corpuscles of the blood 
It is well known that this question has always been answered 
by hypothesis based on very slender foundation. 
The old view, as to the origin of the red blood-corpuscles, 
was that the nucleus of certain colourless corpuscles became 
red and escaped as a free nucleus, the homogeneous red blood- 
corpuscle. 
Later knowledge as to the red coloration of the whole of the 
mother-cell of the red corpuscle led to the assumption that the 
nucleus became atrophied and the whole cell converted into the 
non-nucleated red corpuscle. The attempts which have been 
made from time to time during the past few years to detect a 
nucleus in some form or other in the red mammalian corpuscle, 
point to a foregone conclusion in favour of this total con- 
version. 
Professor Eindfleisch has, however, seen, both in embryos and 
more advanced individuals, the steps in the transformation of the 
red-coloured cell of the marrow into the non-nucleated red cor- 
puscle which demonstrate that the nucleus of the red coloured 
cell escapes and atrophies whilst the body of the cell contracts 
and becomes the red corpuscle. 
He gives figures of the red cells with their nuclei in the act of 
escaping, lying just on the limit of the cell-body or protruding 
from or even hanging by a mere thread to the latter. Then 
beside these he has seen and figures the freed nucleus and the 
irregular collapsed coloured body of the cell, which will soon be 
shaped by pressure and rolling into the disc-form of the circu- 
lating red corpuscle. 
Professor Eindfleisch has endeavoured, but unsuccessfully, to 
witness under his own eyes the actual extrusion of a nucleus 
from a red cell. At the same time the intermediate series of 
forms observed by him are very strong evidence in favour of the 
view which he takes. 
It seems also that Professor Eindfleisch's view is supported by 
certain facts of comparative anatomy which he has not himself 
adduced in its favour. In the Chsetopodous and some other worms 
the nuclei of the vascular walls are often loosened and float in 
the blood as corpuscles. They are not impregnated by haemo- 
globin but the plasma, in which they float, is. Whence comes 
the haemoglobin of the plasma ? Clearly the cells forming the 
walls of the vascular system in certain regions are in the Chae- 
topoda as in Vertebrata, haematogenous ; in them as in Verte- 
brata, the body of the cell forms the haemoglobin which in this 
case becomes liquid instead of retaining the form of a corpuscle, 
