BY MOLECULAR COALESCENCE. 131 
the part be examined in glycerine. And, as this tissue 
polarizes light much better than the phosphate of lime, 
either in perfectly or imperfectly formed bone, the polari- 
‘scope can be employed with greater advantage in inves- 
tigating the structure and the mode of formation of this 
form of vegetable tissue than in bone. I have merely 
mentioned this vegetable substance incidentally, being 
led to it by its resemblance to bone ; but I hope to consider 
it more fully at some future period. I shall next proceed 
to consider the formation of some of the less dense kinds 
of tissue. Having, in the preceding pages, shown, as far 
as experiment and induction can show, that the molecules 
of what are called hard tissues, owe their curvilinear dis- 
position to the direct operation of physical force, it may 
reasonably be expected that the molecules of the less 
dense ones owe their curvilinear arrangement to the same 
cause, and that the process of coalescence above de- 
scribed is as applicable to soft as to hard tissues, whether 
they be animal or vegetable provided only, in both cases, 
these molecules are brought under circumstances alike 
favorable tor its operation. As it is certain that the ele- 
mentary constituents of these two classes of tissues, before 
they are combined to form living organs, are alike affected 
by gravity, it is inconceivable, that a difference in this 
respect should be occasioned merely by these same ele- 
ments being associated with different proportions of fluid, 
or that the molecules composing a spherule of globular 
carbonate of lime, and those composing a spherical particle 
of mucus, should, under similar circumstances, be brought 
exactly into the same form by the agency of the most 
dissimilar forces; and more especially, as it has been 
shown by the plainest arguments, that, the force of gravi- 
tation being all that is necessary to give the particles 
