ITS DIFFERENT PHASES OF DEVELOPMENT IN THE ANIMAL SERIES. 79 
it is as yet uncoloured or presents colour only in its interior, then we find but little 
difference between it and the cellseform nucleus of the nucleated cell, either in the 
inode in which it refracts light, or in which it is affected by water or acetic acid. 
Even when fully red, the “ red corpuscles” are not all equally affected by the action of 
water or acetic acid ; some being always seen which resist to a greater or less degree 
the action of these reagents. Such corpuscles have been considered to be advanced 
formations, they appear to me on the contrary to be recent. 
95. From this it appears that the “ red corpuscle” in its advanced stage does not 
differ, in the respects under consideration, more from the cellseform nucleus of the 
nucleated cell than it does from what is undoubtedly itself in an early stage. The 
differences mentioned therefore argue nothing against the identity of the cellseform 
nucleus and the “ red corpuscle.” 
96. There being thus no evidence to the contrary effect, the correspondence in 
size, form and structure, between the cellseform nucleus of the nucleated cell and the 
“ red corpuscle” of the blood of the Mammifera, which I have now demonstrated, 
will I believe be admitted to constitute pretty forcible evidence as to their identity. 
Whether any additional evidence can be adduced will be seen in the sequel*, 
par. 106. 
97. If the view of the origin and nature of the “ red corpuscle” of the fully-formed 
blood of Man and the Mammifera which I have now given be correct, this “red cor- 
puscle” must be considered as a third phase of development of the blood-corpuscle, 
and of which there occur uncoloured and coloured stages. This third phase I pro- 
pose to call the phase of free cellceforrn nucleus 
98. The different phases and stages of development of the blood-corpuscle in the 
Vertebrata, such as I have now traced them, may be summed up thus: — In all the 
vertebrate animals examined, oviparous, and mammiferous, we find blood-corpuscles 
in what I call the first phase of development, or phase of granule-cell, this presenting 
* The view of the nature of the “ red corpuscle” of the fully-formed blood of Man and the Mammifera which 
I have now propounded, must not be confounded with Valentin’s view that the blood-corpuscles are nuclei, 
seeing that he makes no distinction between the blood-corpuscles of the oviparous Vertebrata and those of the 
Mammifera in this respect. Considering them as analogous to each other, he views them equally as nuclei. 
The nuclei of the “ red corpuscles” of the oviparous Vertebrata he considers to be nucleoli. According to my 
view, on the contrary, the "red corpuscles” of the blood of Man and the Mammifera are not the analogues of 
the "red corpuscles” of the blood of the oviparous Vertebrata, but strictly the analogues of their nuclei, as 
also of the nuclei of the nucleated "red corpuscles” of the blood of the early mammiferous embryo. 
Messrs. Gulliver and Remak have made observations on the blood of the Horse, from which they have inferred 
that the "red corpuscles” are formed within the "colourless ones,” and that they become free by solution of 
the latter. Gulliver however represents colourless corpuscles containing, some one, some two, and some 
even four "red corpuscles,” and these nearly as large as the free " red corpuscles” of the animal. Remak, in 
like manner, speaks of one or more “ red corpuscles” being formed within the colourless ones. Such appearances 
I have never observed. 
f It appears almost unnecessary to remark, that this view of the nature of the "red corpuscle” of the fully- 
formed blood of Man and the Mammifera, completely sets aside the vexed question of a nucleus. 
MDCCCXLVI. M 
