PHYSIOLOGICAL PART. 
Havine in the preceding pages considered, somewhat at 
length, the mode of formation and the structure of 
calculi artificially prepared, the subject of crystalization, 
and the process of final molecular disintegration, I shal] 
now proceed to apply the facts elicited in the course of 
these inquiries to the explanation of the analogous forms 
of carbonate of lime, as they are found in organized 
bodies. 
I shall first consider the perfect similarity as to structure 
which exists between the artificial and natural products ; 
and then consider the identity of the laws under which 
both classes of substances are produced; after which I 
shall show, that the same physical laws of formation 
extend to other natural structures, both animal and 
vegetable. But as my time will not permit of more than 
a limited application of these laws to organized structures, 
I shall chiefly confine my observations to the structure 
and formation of shells and bone, the mode of formation 
of pigment and some other cells, and the structure and 
development of the crystalline lens. It may be observed 
that, as the natural products will be shown in the following 
pages to have been formed upon precisely the same phy- 
sical principles as the artificial ones, and as it is in the 
latter only that their mode of formation admits of being 
