To this category belong, in the first place, cases in which the contents of the fat-cells vary from the natural character; in the second place, cases in which the cells themselves deviate from the normal type.

(a.) The fat-texture manifests, under certain conditions, anomalies for the most part referable to the nature of the contained fat;

(a.) The latter being sometimes preternaturally diffluent, like oil-fat (oleine). It is more than usually unctuous. On pressure or incision it gushes forth abundantly, and in big drops. In the dead subject, neighboring parts are often found infiltrated with liquid fat. It is mostly tinged of a deep yellow, and resembles marrow.

These characteristics very commonly attach to the fat of the old and cachectic, laboring under osteoporosis (from atrophy), extensive ossification of the arteries, osteomalacia; and of younger individuals a prey to cancer. Similar properties belong in an especial manner to fatty accumulations usurping the place of muscle or of pancreas-texture.

(/B.) The fat contained within the cells is firmer, stearine-like, resembles mutton suet, and dulls the blade of the scalpel. The entire fat of the individual is of this character, more especially that of the subcutaneous adipose tissue, and it is commonly associated with strongly developed pigment formation in the rete mucosum, and a copious secretion from the sebaceous glands, - an oily skin. These properties mark, in an especial degree, the fat of younger dram-drinkers, and are almost without exception concurrent with lardaceous affection of the liver.

This variety may be caused by the fat containing a larger proportion of margarine; perhaps, also, by the development of stearine. Spirit-drinking has a very marked tendency to produce it.

(b.) The fat-texture gives evidence of anomalies both as to the contents of the fat-cells, and as to the properties of the cell itself.

The cholesteatoma of Johannes Muller belongs to this class. It is invariably a local, circumscript new growth. The cholesterine holding stratiform fat-mass consists of thin, sometimes concentrically stratified, mother-of-pearl like, lustrous plates of scales, which, on a closer inspection, appear composed of partly spherical and oval, but for the most part polyedrical vegetable-like cells, one-eighth to one-sixteenth of a millimetre big. This texture accords with that of the tallowy, adipose tissue of the wether, only that the cells are smaller and more delicate. The majority of the cells do not appear nucleated; many others, however, more especially the younger spherical cells, show distinct nuclei.

Between the layers of this polyedrical cell-texture are visible crystalline deposits of fatty substances, mostly in the shape of rectangular tables. Barruel found them to contain cholesterine and a fat akin to stearine. The cholesteatoma commonly occurs encysted within a fibroid envelope, or within a cyst-membrane lined with a delicate epithelium. We have, in common with other pathologists, seen it thus in the subcutaneous areolar tissue, in bones, - those of the skull in particular, - in the pia mater, and in the brain. Johannes Miiller met with it in cysto-sarcoma. It also occurs free, in the shape of a layer, as Cruveilhier has observed in urinary fistulae, and Johannes Miiller and myself upon the surface of an ulcerating mammary cancer. In our own case it was upon the sore surface of a fibrous cancer combined with epithelial cancer. We have met with it in the same combination upon the surface of a sloughing ulcer.

The cholesteatoma is in itself innocent. Inclosed within a cyst it usurps the place of surrounding textures, causing the forcible expansion of the osseous texture in bone, and occasionally perforating the common integument, when subjacent to it, becoming destroyed, and thrown off.