72 Ossification Process in Birds, &c. By Br. L. Schdney. 
Aeby as the inquirer who first maintained this blood formation. 
Aeby, however, only conjectured this blood formation on the ossifica- 
tion border in the cited work of his, On the Symphisis Pubes of 
Man, with contributions to the study of Hyaline Cartilage, and its 
Ossification," * as I shall show. 
On page 54, i. c, he says : " The quantity of blood-corpuscles 
is surprising, which is found sometimes in the marrow-spaces, even 
long before the formation of vessels, and if it is possible, nay 
probable, that the same have entered from elsewhere, the circum- 
stance, however, that next to the cells there are often found most 
numerous nuclei-like formations, entirely analogous in size and 
form to the blood-globules, and the most gradual transitions of 
which, specially as regards the flattening, unto the ready-formed 
blood-corpuscles, are met with, justifies the inquiry whether or not 
there exists between both a genetic connection. My own researches 
in this direction have not led to any result." 
From this it follows that Aeby guessed the new formation of 
red blood-corpuscles on the ossification border, and expressly 
declares that his investigations, as regards the new formation of 
blood, led to no result ; whilst Heitzmann maintained this new 
formation as a fact. 
I cannot recognize the validity of the arguments which 
E. Neumann urges against Heitzmann's exposition ; for instance, 
he finds it incomprehensible that the hamatoblasts are coloured by 
carmine, whilst the ready-formed blood-corpuscles, as we know, 
are not. 
But Heitzmann expressly says that the hamatoblasts, homo- 
geneous, yellowish, lustrous, small particles, represent the infancy 
stage of the protoplasm, and that from them, afterwards and after 
undergoing certain changes, proceed real red blood-corpuscles. 
Bodies in the young condition no doubt have different reactions to 
colours to what they have when old. 
E. Neumann further misses the nuclei in the hamatoblasts ; 
and because he adopts the usual opinion that the blood-corpuscles 
in their infancy do possess nuclei — afterwards, however, none — he 
is unable to look upon the hamatoblasts as red blood-corpuscles 
in their stage of infancy. 
My researches are specially adapted to clear up this point. 
El. Metschnikow t found in the embryo fowl first blood- 
corpuscles little coloured and having nuclei, and afterwards dis- 
tinctly-coloured but non-nucleated blood-corpuscles ; and concluded 
therefrom that the latter originated in the former. This conclusion 
is not quite justified, because from one and the same source blood- 
corpuscles may originate, which at first are less and afterwards 
* • Zeitschrift fur rat. Med.' 3te Keihe, 4ter Bd. 1858. 
t Virchow's ' Archiv,' 41 Bd. 1867, " Zur Entwickelimgs-geschichte der. 
rothen Blutkorperchen." 
