We have here, in the first place, to bring forward and to examine in detail the substances which constitute new growths.

1. Protein Substances

The primitive form in which these emerge from their solutions, is that of a structureless or glebous mass, in various degrees of coagulation, and that of an elementary granule down to a pulverulent point-mass. The reason for their appearance in these forms, that is, the reason for the general coagulability, and a fortiori for their specialities of form and coagulation, is quite obscure. That which spontaneously undergoes rapid and firm coagulation passes current for fibrin; that which coagulates more slowly and less perfectly under a manifest progressive change in the medium of solution, for albumen. The molecular form appertains in particular to the higher grades of oxidation of the protein substances (croupous and pyin-holding fibrin). Since the influences which produce the coagulation and precipitation of albumen in experiments, do not presumably take place within the organism, the discovery of the modifications suffered by albumen through the agency of water, acetic acid, and the like, is highly deserving of attention.

The protein deposits are insoluble in ether and in mineral acids. By acetic acids they are rendered translucent, and ultimately dissolved. By caustic potash and fuming hydrochloric acid they are slowly dissolved - by the latter with a lilac tint. An aqueous solution of iodine colors them yellow.

The glutinous and horny substances emerging out of the protein-substances are amorphous, or have a glebous or a stratiform, elementary composition. In their physical properties they approximate, more or less, according to their grade of perfection, to gluten and to urea; in their chemical reaction, to various modifications of gluten (gluten, chondrin, pyin, &c), and of urea.

2. Fats

Their elementary form of occurrence is that of drops, or of an amorphous solidification; of granules; of crystals. Little is known concerning the nature of fats originating thus, more especially of those assuming the form of granule (elementary granules, both free and in-celled, discrete and aggregate), or developed out of blastemata and textures through conversion of protein-substances, and probably even of gluten.

The fats cognizable by their form and chemical relations are:

(A.) Elain

It occurs in variously-sized drops, both free and incelled. In this form it is usually set free out of emulsion-like compounds; in the form of elaic acid, out of saponaceous compounds, or out of combinations with other fats, for example, in exudates, in medullary carcinoma. It frequently represents an eflfusion of the contents of fat-cells, consequent upon gangrenous or ulcerous destruction. The drops resist the action of water and of acids, but dissolve on being boiled with potash, and still more readily in ether or heated alcohol.

(B.) Margarin And Margaric Acid

These occur in microscopic needle-cyrstals, for the most part aggregated in stellate groups or bundles. In this shape the margarin emerges, after the body has become cooled, from its solution in elain, either within the fat-cells, or without. The crystals of margaric acid, soluble in concentrated, heated alcohol, are, according to Vogel, probably a product of decomposition, wrought out of the margarin of the fat, it may be, by a free acid, so often developed in gangrene.

(C.) Cholesterin

When cognizable as such, it occurs in tabular crystals, representing rhombic planes. Many, however, of the aforesaid fat-granules are likewise cholesterin. It almost always occurs along with other fats, and often very copiously; for instance, in gall-stones, in the atheroma of arteries, in encysted tumors. The fact of cholesterin so frequently occurring in fluid and solidified protein substances during their disintegration, - as in exudates, in tubercle, in stratiform coagula upon the inner coat of arteries, renders it probable that, like other fats, it is the product of a decomposition of the elements of those substances. This seems to us more probable than that it exists preformed in combinations which cause it to be held in solution. Its detection in the blood does not appear to us a valid objection to this. It is soluble neither in water, nor in acids, nor yet in alkaline solutions, but only in ether and heated alcohol.

(D.) Stearin

Its occurrence is not proved with certainty, although, under certain conditions, in which fat assimilates to the suet of the wether, not quite improbable.

3. Pigments

(a.) Black, brown, russet-yellow pigment (See "Pigment"), in the shape of molecular granules; the last two occur, also, adherent to microscopic crystals of ammonio-phosphate of magnesia.

(b.) Bile-pigment, as a finely granular precipitate of a yellow-brown color, insoluble in water and in most of the acids, - soluble in a boiling potash-solution, with a greenish-brown tint. Nitric acid destroys it, after causing it to pass through phases first of green, then of blue, and lastly of red coloration.

4. Litliic Acid And Lithates

(A.) Litliic Acid

The fundamental type of its crystals is the rhomboid prism, which, however, often appears cut down to a rhombic plane. The crystals, frequently seen grouped into rosettes (Simon and Vogel), are difficult of solution in water, insoluble in acids, alcohol, and ether. Potash causes their gradual solution. They occur in the urine.

(B.) Lithate Of Ammonia

Lithate Of Ammonia, as a finely granular precipitate, colored of a dingy yellow, yellow-red, russet, rose-tint; difficult of solution in cold water; less so in hot. The effect of acids is to isolate the lithic acid, which, under the microscope, is then seen to develope its crystals.