16 PREPARATION AND MOUNTING 
Teeth may be treated in the same manner as bones, except 
for the examination of the enamel, which is best effected by 
sections and grinding. For that purpose developing teeth 
should be chosen, as in them the enamel prisms are most 
easily isolated. 
5rH DIvIsION. 
As the solution of animal and vegetable tissues generally 
means the confusion or destruction of their histological 
elements, not much can or need be said of it here, except 
that it may be as well to indicate the special solvents and 
tests of the special components of all tissues, since it is upon 
a correct knowledge and appreciation of the degrees and 
differences of the action of these, that effective histological 
research must chiefly depend. 
Albumen, when pure, is nearly insoluble in water, wholly 
so when coagulated by heat. In dilute caustic alkali it 
dissolves with facility. Solution of nitrate of potash, acetic 
aud tri-basic phosphoric acids, and pepsine, dissolve the pur- 
est form of albumen procured from white of egg. 
Fownes observes, “that it must be remembered that a 
considerable quantity of alkali and very minute quantities 
of the mineral acids, prevent coagulation by heat, and that 
the addition of acetic acid, indispensable to the test by mer- 
cury, produces the same effect.” 
Fibrine of blood is insoluble in both hot and cold water, 
but is partly dissolved by long-continued boiling. ‘Fresh 
fibrine, wetted with concentrated acetic acid, forms after 
some hours a transparent jelly, which slowly dissolves in 
water. Very dilute caustic alkali dissolves fibrine completely. 
Phosphoric acid produces a similar effect. Fibrine of flesh, 
which is not identical with that of blood (Liebig), is soluble 
in cold water containing one-tenth of hydrochloric acid. 
Casein is only soluble in water in the presence of free 
alkali in very small quantities. It is partly soluble also in 
very dilute acids. 
