BY MOLECULAR COALESCENCE. PEF 
appearances first presented by the earthy deposit, or of 
the arrangement and form it assumes in a short time after 
its precipitation. The osseous tendons which I have found 
to be well adapted for this examination, are those of the 
dorsal muscles of any young bird. In the parts of 
these tendons where the ossification is just beginning, 
minute scattered particles can be seen taking somewhat 
the course of the tendinous fibres. On the same 
tendon, rather nearer to this muscle, these particles 
being more numerous, lie close together, and extend in 
patches, of no definite form or size, along with its fibres. 
In some of these patches, when examined by transmitted 
light, darkish, ill-defined spots can be seen, arising, I have 
no doubt, from a deficiency of the earthy matter at these 
parts, and the accumulation of it in the parts around. In 
others, where the earthy matter is much less in quantity, 
the particles can be seen to have arranged themselves in 
circles, more or less complete. As there can be no ques- 
tion but that the process of ossification in these tendons 
is essentially the same as in other parts, and that it is 
identical in all classes of animals, I shall contimue the 
description of the appearances presented by the earthy 
deposit, as I have seen them in the bones of the reptile, 
the fish, and the human subject. There are two forms in 
which the ordinary process of ossification may be studied ; 
one, where the ossifying process is confined to isolated 
portions of earthy deposit; another, where the bone in 
process of development is connected with perfectly formed 
bone. The former can be seen very well in the young 
frog, or in a very young fish. (Fig. 7 is a representation 
of the appearance presented by the particles of phosphate 
of lime taken from a frog about one inch in length, 
and with no other dissection of the part than was neces- 
