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opaque fluid or emulsion, which in structure exactly resembles milk. 
That is to say, it consists of molecules composed of a drop of oil 
surrounded by a layer or membrane of coagulated albumen. Such 
compound molecules possessing the property of endosmose may there- 
fore readily be produced artificially, and by trituration can be reduced 
in size so as to resemble the elementary molecules in chyle or in the 
yolk of the egg. If oil and albumen be introduced into the stomach 
and intestinal canal, they are always so reduced; and one of the objects 
of digestion would appear to be separating from the food, and render- 
ing fluid its oil and albumen, so as to produce the chyle molecules 
which are ultimately transformed into blood. Indeed, everywhere in 
living organisms it may be observed, that oil and albumen formed as 
secretions by plants, and entering the bodies of animals as food, either 
separately or united, constitute the chief origin of molecular formations. 
Mr Rainey has recently pointed out the condition which causes 
molecular mineral matter to assume the form of rounded nuclear 
bodies.* This condition is viscosity. If carbonate of lime be dis- 
solved in water, the forms produced on its precipitation are crystal- 
line ; but if the fluid be glutinous, composed, for example, of fluid, 
gelatine, or gum, the forms produced are oval or globular. Preci- 
pitations made in this way on slides of glass, closely resemble the 
appearances called nuclear or cellular in different stages of develop- 
ment. Mr Rainey has further shown how starch granules are 
produced in the juices of vegetables by the endosmose of gum 
into a cell containing a solution of dextrine.f In the same manner 
that the contact of oil and albumen produces oleo-albuminous mole- 
cules, so does the contact of gum and dextrine precipitate starch 
molecules. In this manner we can comprehend how the mixture 
of various organic fluids gives rise to particles of different kinds. 
Histolytic molecules are the result of the transformation and 
disintegration of fluid and solid substances by chemical or mechanical 
action. They are generally larger in size than histogenetic molecules, 
are more purely fatty, and from being associated with the debris of 
broken-down texture may, in most instances, readily be distinguished. 
Thus, in the breaking up of cells and of muscles wRen they become fatty, 
* On the Mode of Formation of Shells of Animals, of Bone, and of several 
other Structures, by a process of Molecular Coalescence, &c. By George 
Rainey, M.E.C.S. London, 1858. 
f Microscopical Journal, 1859. 
