DISTINCTIVE CHARACTERS OF ORGANIZED BODIES. 17 
CHAPTER I, 
OF THE VITAL OPERATIONS OF ANIMALS, AND THE INSTRUMENTS BY 
~ WHICH THEY ARE PERFORMED. 
1. Lrvrye beings, whether belonging to the Animal or to 
the Vegetable kingdom, are distinguished from the masses of 
inert matter of which the Mineral kingdom is made up, by 
peculiarities of form and size, of structure, of elementary 
composition, and of actions——Wherever a definite form is 
exhibited by Mineral substances, it is bounded by’ plane 
surfaces, straight lines, and angles, and is the effect of the 
process of crystallization, in which particles of like nature 
arrange themselves on a determinate plan, so as fo produce a 
tegular aggregation ; and there is, probably, no Inorganic 
element or combination which is not capable of assuming such 
a form, if placed in circumstances adapted to the manifestation 
of its tendency to do so. The number of different crystalline 
forms is by no means large ;" and as many substances crystal- 
lize in several dissimilar forms, whilst crystals resembling one 
another in form often have a great diversity of composition, 
there is no constant correspondence between the crystalline 
forms and the essential nature of the greater number of 
mineral substances. If that peculiar arrangement of the 
molecules which constitutes crystallization should be wanting, 
so that simple cohesive attraction is exercised in bringing 
them together, without any general control over their direc- 
tion, an indefinite or shapeless figure is the result. With 
this indefiniteness of form, there is an absence of any limit 
whatever in regard to size: a crystal may go on increasing 
continuously, so long as there is new material supplied ; but 
i new material is deposited upon its surface merely, and 
addition involves no interstitial change ; the older particles, 
which were first deposited, and which continue to form the 
nucleus of the crystal, remaining just as they were. In Or- 
bodies, on the other hand, we meet with convex 
3 and rounded outlines, and with a general absence of 
3 and the =. grades, both of Animal and of 
