In form the cells of Growths are sphe roidal, as in sarcoma ; or ovoid, as in enchon droma ; and plump, or flattened, and discoid, in proportion to the abundance of their con tents.
In respect of size they vary within wide limits, from the simple fact that it is the nature of some to go on increasing in bulk (for instance, the cells of colloid and of en chondroma), of others to retain persistently the dimensions originally acquired. This ana tomical distinction is connected with a very important physiological difference in the mode of increase of Growths. We do not depart much from the truth in assigning vh-o- and wt-u of an inch as the extreme measurements of' these bodies. Further, the cells of the same Growth vary in size, independently of endogenous enlargement.
Cells are either set beside each other, and cohere by their contiguous walls, or they re main free.
The thickness and transparency of the wall of cells vary; the wall may be collapsed and corrugated, or stretched and smooth ; the nucleus (when this exists) of the cell may be distinctly parietal or not.
The contents of cells are of four kinds :— fluid ; granules ; nuclei; young cells. Fluid, in more or less abundance, is constantly pre sent in sound cells ; upon its amount mainly depends the plump or shrivelled aspect of these. Granuks exist in abundance in the cells of sarcoma and of scirrhus. A free nucleus may be found sometimes in the cell of colloid cancer and of enchondroma. Young cells,themselves provided with a free or parietal nucleus, are seen in the interior of the large cells of the two Growths just named.
(c.) The next element requiring consider ation is the Arucleus. Nuclei are found in the great majority of Growths; either free, in connection with cells (parietal or central), or attached to fibres. Free solid-looking cor puscles are found in the substance of scir rhus; these appear (whether generated free as they are seen, or originally connected with cells, and released by the disintegration of these) to be the germs of future cells. Of the parietal and central nucleus enough has already been said. The slightly granulated look of the fibres of Fibrous Growth depends on the permanent character of their nuclei, which appear set superficially in their sub= stance. In whatever condition nuclei exist,
they are distinguishable commonly by their comparative opacity; this is rendered more obvious by acetic acid, which increases the transparency of cell-walls, or by ioduretted solutions, in consequence of the tendency of nuclei to absorb coloured matters.
(d.) Ftbrils.—Fibrillar substance occurs in Growths in many varieties of form and de grees of abundance.
Peculiar fibres, of excessive transparency and delicacy, constitute the chief mass of the " fasciculate" variety of cancer. " It is im possible," as we have elsewhere said, " to look at these fibrils without being struck with their similarity to those of the buffy coat of the blood, or without conceiving the idea that blastema has been produced in connection with extravasated blood." Fibres, differing but little from those of natural fibrous tissue, form the staple element of fibrous Growths, and are abundant in scirrhus.
An appearance of fibrous structure is pro duced in some Growths by linear juxtapo sition of fusiform or straight caudate cells. These corpuscles have the aspect of spherical cells with two opposite points of their periphery prolonged into very minute tapering fibrils. (See fig. 93, p. 127.) Usually single, the fibril is sometimes biH. The cell is obscurely nucle ated, and frequently granulated; excessively abundant in sarcoma and cysto-sarcoma, ap pearing occasionally in hcematoma, cystoma, angeiectoma, melanoma, and carcinoma, they cannot be discovered in fibroma. Their pre sence signifies that of blastema of simple plastic character; and there is no certain evidence that the proper cell of cancer (in which formation they were at one time sup posed to be of peculiar significance) is capable of assuming the perfectly fusiform shape. Our opinion on this point has of late grown much more decided. A shapelessly caudate cell, with irregularly curved fibrils, or lateral superadded fibril, is more closely allied to cancer, and will be described with that product.