120 FORMATION OF SHELLS OF ANIMALS, ETC., 
very beautifully in the lamina spiralis of a child, aged 
six years. In this case, the particles of phosphate of lime 
are minute, but spherical, and show decided indications of 
coalescence. I have in my possession a preparation show- 
ing this fact very distinctly. It is scarcely necessary to 
say that I have not mistaken the arches formed by the 
cochlear nerves for bone. But the best of all subjects for 
demonstrating the fact of molecular coalescence, is the 
very young fish, in which occasionally the globular par- 
ticles, containing probably a larger proportion of carbonate 
of lime mixed with the phosphate than is contained in the 
bones of other classes of animals, exhibit, under polarized 
light, a dark cross, like the artificial globular particles, 
and like many of those found in shells. Now, I may 
observe, that in all these examinations of the imcipient 
stage of ossification, as seen in the tendon of the bird, 
in membrane, and in cartilage, all these parts have been 
in as normal and unmutilated a state as possible, yet I 
have never been able to see anything like the six develop- 
ing bone-cells depicted and described by Professor Kolliker 
in his manual of Histology, namely, “simple bone-cells ; 
compound ones running to a parent-cell, with two secon- 
dary cells, each arising from free cells,from rickety bone,” p. 
84, English translation. (It would have been better if Pro- 
fessor Kolhker had selected specimens intended to illustrate 
the normal structure of healthy bone, from sound rather 
than from rickety bone. Are specimens of developing bone- 
cells, exhibiting the appearances represented in the plate 
alluded to, so difficult to be obtained from an unsuspected 
source, that Professor Ko6lliker is obliged to get them 
from a suspected one? At any rate, this is not the 
simplest way of prosecuting the mquiry. By employing 
a tissue im an abnormal state to illustrate its normal 
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