ITS DIFFERENT PHASES OF DEVELOPMENT IN THE ANIMAL SERIES. 67 
in their degree of development, and not to be confounded together under one specific 
name or epithet, whether “lymph” or “ colourless.” 
24. Granule Blood-cells . — The corpuscle in the blood of the Frog, clearly identical 
with the granule blood-cell of the Skate in the coarsely granular stage, is roundish, 
and contains clear granules strongly refracting the light, like those of the same cell 
in the blood of the Skate, only not so large (fig. 1 a.). These granules are usually 
collected in greater number to one side. The cell itself I have seen, on carefully 
watching it in blood drawn from the living animal, exhibiting changes of shape with 
movements of the granules, such as have been above described in regard to the 
granule-cell of the Skate (par. 7 et seq.). 
25. By the addition of water this granule blood-cell becomes somewhat distended, 
and if then very much diluted acetic acid, or rather to express myself more cor- 
rectly, water very slightly acidulated with acetic acid, be added, the granules are 
dissolved and a cellaeform nucleus about a sV oth of an inch in diameter comes into 
view (fig. 1 h.). If stronger acetic acid is added, instead of one such nucleus, the ap- 
pearance of two or more smaller ones lying close together is apt to be presented. 
26. The granule blood-cell in the finely granular stage of the Frog, when by the 
action of water it has become distended, presents itself of a regular circular form with 
a diameter usually about -oiroth or j^ooth of an inch, but sometimes greater, some- 
times less (fig. 2 h.). It contains an indistinctly granular matter which does not 
refract the light much, and therefore it appears very pale. 
2 7- Before being acted on by water, the cell under consideration usually presents 
itself of an irregular shape with processes shooting out from it (fig. 2 a.). After the 
blood is drawn, it rapidly undergoes the change to this shape, which, it is to be ob- 
served, is somewhat analogous to the change of shape which the coarsely granulous 
blood-cell presents. 
28. When by the action of water the cell has been distended, a cellseform nucleus 
is sometimes already visible in the interior through the finely granular contents 
(fig. 2 h.), but by the action of acetic acid one is always brought distinctly into view. 
The diameter of this cellseform nucleus in the state of distention in which it is seen, 
may be put down at about ^Vo th of an inch. 
29. Instead of one cellseform nucleus of this size, an appearance of two, three, or 
even four smaller ones, may be brought out (fig. 2 c.), and this even more readily than 
in the case of the coarsely granulous cell (par. 25.). I am satisfied, however, that this 
is in both cases merely an appearance produced by the shrivelling together of the 
walls of the single cellseform nucleus in consequence of the action of the acetic acid. 
30. It is proper to observe, that I have come to this conclusion only after having 
particularly tested the point by repeated, careful, prolonged and varied observations. 
Nor is the determination of the point of small moment, as on the appearance of a 
multiple nucleus which I have thus shown to be artificially produced, and on a similar, 
but I believe equally artificially produced appearance of a multiple nucleus in the 
