ORIGIN OF RED BLOOD-CORPUSCLES. 
347 
abundant in blood which is undergoing repair than in 
normal blood. Certainly it may be that they are marrow 
cells which have accidentally fallen into the blood current^, 
but it is, perhaps, more logical to look upon them as leu- 
cocytes which have accidentally undergone a hsemoglobic 
degeneration after the fashion of marrow cells or the hsema- 
tids of oviparous animals. In any case the extreme rarity 
of these elements takes away from them any value in the 
solution of the problem of haematogenesis. 
Lymphoid Latches in the Ltabhit. — MM. Ranvier and 
Hayem have recently held that hsematids being devoid of 
nucleus were necessarily endogenous cellular productions. 
M. Ranvier has brought to bear upon this subject his 
observations on the lymphoid patches in the mesentery of 
the rabbit where he has thought he has seen and has 
figured hsematids originating in the midst of angioplastic 
cells destined to become the walls of the vessels. But 
admitting the perfect accuracy of the observations of such a 
skilful anatomist, it must be allowed it would be very 
difficult to ascribe to them such a character. In this 
case it would follow that the constant repair of the 
blood is necessarily bound up with the productions of new 
capillaries, and that the restoration of the blood after great 
hemorrhage is accompanied by a considerable extension of 
the capillary system ! It has not yet been shown that this 
is the case.i 
Blood undergoing Repair , — It only remains to examine the 
conditions which blood presents among mammals while under- 
going repair after great haemorrhage. Observing the blood 
under these conditions one is struck with the extraordinary 
abundance of globulets, and above all, by the number of 
intermediate forms between the globulets properly so called 
and the elongated oval hsematids which I described above ; 
and no doubt these are all the same, passing from one form 
to the other. 
They are very easily seen in the dog. I have also observed 
them in the rat. It is only necessary to subject these animals 
to copious and frequent bleeding The globulets of Donne 
(haematoblasts of M. Hayem) appear to me, as Zimmerman 
suspected, and as M. Hayem admitted, to be the true origin 
of the hsematids of mammals. They represent the young 
state just as the microcytes of MM. Vanlair and Masius 
represent the old and decayed state. 
' A tiling which [circumstances only very rarely allow one to study, and 
which would be of considerable interest in this connection, is the mode, of 
repair of the uterine mucous coat during an intermcnstrual period. 
