ORIGIN OF RED BLOOD-CORPUSCLES. 
345 
The first point we wished to know is then well estab- 
lished. 
It is also certain that many of the marrow cells undergo a 
haemoglobic degeneration altogether comparable to that 
undergone by the haematids in circulation in the blood of 
oviparous animals. The protoplasmic body, at first colour- 
less and finely granular, soon becomes hyaline, coloured, and 
refractive. At the same time the nucleus gradually loses its 
chemical characters and finally disappears. The peculiar 
red colour of the marrow is due to the abundance of these 
elements. 
The question so often discussed as to the essential identity 
of the marrow elements (medullo-celles of M. Ch. Robin) 
and the leucocytes is here beside the mark. Such identity 
is improbable, and in any case the medullo-celles ” never 
present the characteristic four nuclei found in the leucocytes 
of the lymphatics. We might here call to mind the words 
of the German author of one of the last works on the sub- 
ject, The term white corpuscle has become a sort of omni- 
bus into which everything is thrust.” 
It is now well known that the medullary elements undergo 
haemoglobic degeneration along with a disappearance of the 
nucleus. 
In the less modified elements independent masses of 
haemoglobin appear almost as large as haematids, but pushed 
out of shape by the neighbouring elements. 
It has been proved that before this degree of degeneration 
is attained the masses of haemoglobin contain a nucleus 
which disappears by gradual assimilation into the proto- 
plasmic body as in the vascular area in Rodents, and not by 
going out of the cell, as has recently been stated (G. E. 
Rindfleisch). The question arises do these masses of haemo- 
globin, which have been very properly called medullary 
haematids,” and which are moreover comparable in all respects 
to the haematids of birds, end their retrograde development 
by becoming dissolved, or do they fall into the blood stream ? 
It is impossible to suppose that these elements can exhibit 
spontaneous movements, so as to admit of their displacing 
themselves, or becoming detached from the walls of the 
capillary, and finally passing through the endothelial cells, 
or pushing in between them by a sort of reversed diapedesis. 
One of the essential characters of haemoglobic degeneration 
is the almost immediate loss of all power of amoeboid move- 
ment in the protoplasm. 
On the other hand, can we look to external forces to 
accomplish for the haematid this migration ? No ! for the 
