174 
HISTOLOGY OF ANIMALS. 
of this pus be examined with a power of five hundred 
diameters, a quantity of minute granular matter, readily 
soluble in dilute muriatic acid, may be distinguished 
among the pus corpuscles. This fact I noticed many 
years ago, but Mr. Bransby Cooper has ascertained by 
chemical examination, that a large amount of phosphate 
of lime is present in such pus, and announced his 
discovery in 1843, when Professor of Surgery to this 
College ; so that it would appear that the pus has a 
solvent power, eroding or decomposing the animal 
matter, while the mineral constituent escapes with the 
pus in its granular condition. 
The bone-cells or lacunae vary in size and shape in 
the four great classes of animals, and I have ascertained 
that they bear a direct relative proportion to that of the 
blood corpuscles. # They are largest in reptiles, especially 
those of the Perennibranchiate order. In fishes their 
shape is very peculiar; and, 
what is remarkable, they 
are in some cases similar in 
form to the stellate cells 
found in the specimen of en- 
chondroma from the hand, 
before described and repre- 
sented in Fig. 126, as is 
Portion of tlie scale of a fish, . . 
Lepidosteus osseus. illustrated by a thm section 
* “Transactions of the Microscopical Society,” Vol. ii. 
fig. 136 . 
