70 MR. T. WHARTON JONES ON THE BLOOD-CORPUSCLE CONSIDERED IN 
Examination of the Blood-corpuscles of an Embryo Ox, about 1 ^ inch in length, and a 
comparison of them with those of Oviparous Vertebrate Animals. 
44. The blood of this embryo presented the following kinds of corpuscles : — 
] . Granule-cells in coarsely granular and finely granular stages. 
2 . Nucleated cells in uncoloured and coloured stages. 
3. Small red corpuscles similar to those of the fully-formed blood of the animal. 
45. Granule-cells. — Some of these contained pretty large and well-defined granules 
and refracted the light strongly, — coarsely granular stage (fig. 1 .) ; others presented 
less defined granules, and refracting the light less, appeared very delicate and pale, — 
finely granular stage. Fig. 3 represents one of these cells with the cellseform nucleus 
already visible through the finely granular contents ; this may be viewed as a 
transition to the phase of nucleated cell, whilst fig. 2 represents a granule-cell inter- 
mediate between the coarsely and finely granular stages. 
46. The size of these granule-cells was from about yyYij th t0 about r sVs th of an 
inch in diameter. 
47. Nucleated Cells — Uncoloured stage. — In these, as in the corresponding cells of 
the blood of the Frog, the nucleus, quite cellseform however, was very distinct, present- 
ing a contrast with the scarcely visible cell-wall (fig. 4.). In some, as above described 
in the Frog (par. 36.), the cell-wall closely embraced the cellseform nucleus, so that 
this at first appeared free, until by the addition of water the extremely pale cell-wall 
was brought out. Often the distention of the cell-wall took place on one side only, 
presenting the appearance delineated in figure 5. In some again the cell- wall was 
not only distended but pretty distinct, and even slightly reddish (fig. 6 .). 
48. The size of the cellseform nucleus was from y- 8 V yth to 3 -^ 3 -oth of an inch in 
diameter, and the cell itself in those in which it was distended from about 0 th to 
Xie o th of an inch in diameter. 
49. Nucleated Cells — Coloured stage. — Most of these were circular (fig. 7 a.), but 
some were oval (fig. 8 .). The circular measured about y-gVoth of an inch in diameter. 
The oval measured about y -jg^ th in the long diameter and about yryg-th of an inch 
in the short diameter. The cellseform nucleus, when not at first evident, was brought 
distinctly into view by the addition of very dilute acetic acid, or even of water merely. 
It was circular, and measured from about yiVo ^ 1 t0 about yyygth of an inch in 
diameter (fig. 7 b.). 
50. As to the small red corpuscles similar to those of the fully-formed blood (fig. 9.), 
they were rather larger than in the grown animal. They closely resembled the 
cellseform nuclei of the nucleated cells, only they were red, whilst the latter were 
uncoloured. There were some free corpuscles however uncoloured which resembled 
the cellseform nuclei of the nucleated cells, and also the small red corpuscles minus 
their colour. 
51. Not having yet had an opportunity of examining the blood on its first appear- 
ance in the mammiferous embryo, I do not know if small red corpuscles already 
