Kindred new growths, important from their frequency no less than from the question arising, in every concrete case, as to their innocency or malignancy. They constitute an extensive group, comprising most of the so-called heteroplases. They occur, now as independent tumors, which usurp the place of normal textures, now as throwing out a multiplicity of roots or branches through the textures, interlacing with their elements, destroying these, and assimilating them to their own proper substance.

Solidified, and more especially fluid blastemata enter very largely into their composition, both becoming developed after their own manner into the elements described under the heading, "Metamorphosis of Blastema." They become wrought into a stroma, various in extent and in design, which forms the receptacle for fluid blastema and its elements. Along with the fibrous stroma developed out of solidified blastemata, massive fibrous textures, evolved out of cells and nuclei, are derived also from fluid blastemata. Lastly, the structureless parietes of parent-cells, here so numerous, enter into an immediate fibrillation.

The ulterior development of the parent-cell determines that very common texture, the alveolar, as also the resemblance with certain gland-textures; for example, the salivary glands, the thyroid gland, the cortical substance of the kidneys, etc, resemblances which formerly and even recently gave rise to such designations as "sarcoma pancreaticum," etc. When these heterologous formations affect osseous structures, they often determine the extensive new growth of a texture simulating bone.

Their chemical composition involves, besides the gluten of the fibrous elements, several other gluten-like (pyin-like) substances, along with albumen, casein, and fats.

In size they vary from that of a just cognizable new growth to that of a human head, and upwards.

In form they occur as spherical, roundish, knotty, lobulated, stellate, irregular, ramified tumors. The form of infiltration belongs more especially to cancers.

Of consistency we meet with every gradation, from the fluid and gelatinous, to the consolidated, fibro-cartilaginous.

Bloodvessels enter into the fabric of all these new growths, although to a very different amount; some being, relatively to their volume, sparingly vascularized, whilst others are distinguished by their redundant vascularity. In those of the latter kind, the collapse of the bloodvessels after death occasions a marked change in color, consistence, and volume.

These tumors have a pathology of their own, being especially subject to hyperemia, hemorrhage, and inflammation with its sequelae, more especially ulceration and necrosis.

Many undergo a process of involution and extinction, either spontaneous, or evoked by preliminary disease, especially by inflammation.

They originate at all periods of extra-uterine life, and are occasionally found of considerable size in the new-born infant.

Upon the whole, no texture or organ is exempt from them. There is, however, something peculiar and remarkable in the affinity evinced by certain types for particular organs.

We would distinguish these new growths, as shadowed forth in the heading, into two series, the one comprising innocent, the other malignant formations, for the grounds of which distinction we must refer the reader to the section on "Organized New Growths".

We have selected the term sarcoma to designate the benign growths, not because of any especial analogy with muscle-flesh, but in order to fix and define a name familiarized by long usage, and also by no little abuse. The malignant we shall leave in possession of their ancient characteristic appellation cancer, - carcinoma.

To catalogue the species of these new growths in a strictly philosophical order, is not feasible at this day. We shall best respond to the requirements of practice by determining the species upon the grounds of predominant structural and chemical relations, a due regard being had to the general habitudes of a growth. The varieties, numerous in the instance of certain species, are for the most part concerned with elementary texture, by which the general habitudes are not essentially influenced.