A very frequent heterologous formation, of which there are several varieties. It consists, besides some albumen, almost wholly of a gluten-, chondrin-, or pyin-like substance.

The varieties are principally referable to consistence, which varies from that of gelatin to that of fibro-cartilage, conforming itself partly to the amount of water held by the glutinous basement, partly to that of the textural, and especially the fibrous elements developed within it.

(a.) The first variety is a very soft, jelly-like, nearly limpid, tremulous, yellowish-gray new growth, sparingly vascularized. It is the gelatinous tumor - the collonema of Johannus Muller.

J. Muller describes the parenchyma of collonema as made up of spherules, some of which are much larger than blood-globules, interspersed with crystalline needles.

We have met with the gelatinous sarcoma in different organs; more commonly, however, in the brain, and in the mammary gland, bearing, if not all the attributes of Muller's collonema, at least so close a resemblance to its texture as to remove all doubt as to their identity. Our specimens presented, on the one side, a perfectly embryonic form of collonema, on the other side one more highly developed, and bordering upon the following varieties:

A roundish, goose-egg-sized, gelatinous tumor, from the mammary gland, consists of a very soft, amorphous blastema, interspersed with, for the most part, very minute elementary granules, and delicate little twig-like fibre rudiments. This blastema is permeated by whitish membranous septa, differing from the basement in nothing save in their greater consistency.

A very bulky, lobulated, gelatinous tumor from the brain, displays branched fibres, resembling the elastic, with very numerously imbedded nucleated cells, mostly larger than the pus-cell.

One extirpated along with a portion of the inferior maxilla, exhibited a stroma, consisting of elastic, branched fibres, shooting forth twig-like, out of a stem.

Lastly, a fourth, from a spermatic cord, showed single spiral, elasticlike, but transparent fibres, in an otherwise amorphous, tenacious blastema.

(b.) The second variety comprises a series of kindred new growths, marked by a progressively increasing density and resistance, and mostly by a very pronounced stellate and lobulated structure. A white, areolar tissue-like fibrillation, cognizable with the naked eye, and bearing in its interstices nuclei and cells, caudate nuclei and cells, and nucleus-fibres, enters largely into its composition.

There is here often both a microscopical and also a ruder alveolar texture and cyst-formation, which lend to the heterologous growths the semblance of a glandular structure; the alveoli and cysts being the especial holders of the gelatinous moisture.

This variety of sarcoma is generally endowed with considerable vascularity. During life, the new growth exhibits various shades of redness, and offers to the feel either a woolly resiliency or a greater degree of elastic firmness. In the after-death collapse, it is of a grayish-red or reddish-white, flabby, and in various degrees resistant.

(c.) The third variety consists of a firmish, amorphous basement, broken up into solid fibres, after the manner of the intercellular substance of hyaline cartilage, and teeming with cells more or less resembling those of cartilage. This variety approximates in its elementary structure to the cartilaginous new growths, to the enchondroma, with which the gelatinous sarcoma is manifestly and essentially cognate.

These varieties, more especially the last two, are often found combined in one and the same new growth.

The gelatinous sarcoma, besides the rarer localities specified in the instance of collonema, namely, the brain and the mammary gland, affects the parotis, the subcutaneous areolar tissue, the intermuscular parts, and with great frequency the periosteum and the bones, more especially of the face. The second variety is particularly marked by the immense circumference to which the growth becomes developed, often within a brief space of time, through redundant lobulation and ramification.