16 PiUSJfAilATION AND MOUNTING 



Teeth may be treated in the same manner as bone?, except 

 for the examination of the enamel, which is best effected by 

 sections and grinding. For that purpose developing teetb 

 should le chosen, as in them the enamel prisms are most 

 easily isolated. 



STH 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 th^ action of these, that effective histological 

 research must chiefly depend. 



Albumen, when pure, is nearly insoluble in water, wholly 

 BO when coagulated by heat. In dilute caustic alkali it 

 dissolves with facility. Solution of nitrate of potash, acetia 

 and 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 fre 

 alkali in very small quantities. It is partly soluble also in 

 very dilute acida. 



