ORIGIN OF RED BLOOD-CORPUSCLES, 337 
neglected. It is^ therefore, necessary before going further 
to go over these various points. 
White Corpuscles . — I believe I was the first to describe 
that the leucocytes of man and other mammals have 
always, when completely developed, four nuclei, regularly 
arranged, grouped in the centre of the protoplasm, and 
devoid of nucleoli. This form represents the adult state. 
There are always found besides these other smaller corpus- 
cles, few in number, in the blood, in great abundance in the 
lymph. These have a single nucleus furnished with nucle- 
olus and surrounded by a much reduced layer of proto- 
plasm. These corpuscles are true nuclei of origin, and 
represent the young state of the quadri-nucleated cor- 
puscles. 
They originate in the lymphatic glands, and perhaps also 
partly in the spleen (see below). What becomes of these 
quadri-nucleated corpuscles ? The constant production of 
corpuscles in the lymphatics, the absence, or at any rate the 
invisibility, of any nucleolus in the four nuclei of the adult 
corpuscle, leave little room for the hypothesis that these 
nuclei outlive their protoplasm, and becoming free remake 
nuclei of origin. It seems equally improbable that the 
adult quadri-nucleated corpuscles leave the vessels, as has 
been supposed, to become the differentiated elements of 
more or fewer of the tissues. In any case, the first thing to 
do to support this hypothesis, would be to search in the 
developing tissues for these corpuscles, which are easily re- 
cognisable on account of their four, regularly disposed, nuclei. 
The leucocytes of Semmer are to be found among mam- 
mals as among oviparous animals. They are particularly 
abundant in the horse where M. Semmer has chiefly studied 
them. 
Hed Corpuscles . — I was the first to show that all the red 
corpuscles of mammals have not necessarily — apart from 
accidental injury — the discoidal shape, commonly described 
and figured. Besides the classical red corpuscle, there are 
always others ovoidal or even fusiform in shape. Their 
long diameter is longer than the diameter of the normal 
corpuscle, their edges are slightly turned up. Sometimes 
these corpuscles are even more elongated, terminating it 
may be in a point at each end, as in the rat. 
It must be noted that this is in no way a question of 
accidental stretching. I have directly proved its existence 
in these hsematids in the blood in circulation in mammals. 
AVe shall see directly the importance as regards hfemato- 
geneeis of this form of hsematid, which has hitherto only been 
