A. Fatty Deposit In The Kidneys

We shall examine this subject under the head of Hypertrophy of the Fascia Adiposa.

B. Formation Of Cysts

Although we explicitly exclude the consideration of all encysted tumors which have their origin in a dilatation of the urinary passages, and especially of the calices, we think it necessary at this place to discuss a. Cysts, that occur frequently in the renal parenchyma, and which we cannot positively state to be new formations. We allude to cysts which vary in size from that of a millet-seed, pea, or bean, to that of a walnut or even a goose's egg, and which contain a clear, colorless, or yellowish, serous, alkalescent matter, or a substance of a yellowish or brownish color, and of a melicerous or mucilaginous consistency, or again, of a lateritious, chocolate-colored or inky (melanotic) tint. They are formed by a serous membrane, in which a branched vascular network may be traced. They vary in number; sometimes there is a solitary cyst of one of the above-named sizes; generally there are several of different sizes; and in rare cases, they are so numerous, that the kidney, being proportionately enlarged, appears converted into a collection of cysts varying both as to size and to contents, the renal tissues having given way to them. In very well-marked cases a diminution of the urinary secretion, and its consequences, have been observed. These cysts are chiefly developed in the peripheral layer of the cortical substance, and project above the surface of the kidney, so as to be at once perceptible on the removal of the tunica albuginea.

They occur at every period of life, and are sometimes even congenital.

They acquire additional importance if developed in consequence of renal inflammation, especially when this arises from lithiasis, and more particularly in consequence of Bright's disease.

Our own view, and that of German authors generally, is that they are not the dilated terminations of the Malpighian capillary tubes, but that they consist in a conversion of the cellular layer in the Malpighian corpuscles into serous cysts, resulting from the pressure exerted by the Malpighian corpuscles when tumefied and gorged with the inflammatory product of these diseases upon the surrounding strata. The latter during their metamorphosis take up the vessels of the renal coil (Nierenknauel) for the purpose of the new secretions. It would not be surprising if their contents were occasionally urinous, but we have never been able to discover a trace of urinous precipitates or concretions in them. We have once found a cyst that was seated at the circumference, and was of considerable size, inflamed and ruptured, and its contents effused into the adipose layer.

/3. The acephalocyst is a morbid product that occurs in the kidney; less frequently certainly than in the liver, but more frequently than in any other organ. We have no particular remarks to offer in reference to the relations of this variety of encysted tumor, to its contents, or to the surrounding tissues, except that it occasionally reaches the extraordinary size of a fist or a child's head, and that it may discharge its contents in various directions. The following modes of discharge are important: aa. Communication of the cyst with, and its discharge into, the colon (the ascending or descending colon), and consequent evacuation per anum, and:

BB The communication of the cyst with, and its discharge into, the cavity of the renal pelves and calices. Small acephalocysts, or ruptured larger ones, may thus be conveyed by the ureters to the bladder, and be evacuated, as is particularly the case with females, by the urethra (mictus acephalocysticus), or they induce obstruction and dilatation of the urinary passages by their size.

y. The composite cystoidea rarely occur in the kidneys; though when they are formed, they attain a considerable size. We have in our museum an illustrative specimen, in the left kidney of a boy of five years of age.

C. Anomalous, Fibrous, And Osseous Tissue

We find fibroid masses of various extent and shape developed in the products left by inflammation and Bright's disease; and in rare cases a deposition of osseous substance is effected within them, in the same manner as we find occurring in the fibrous exudations of serous membranes. The calcareous concretions are not however in this case laminae, but irregular tuberculated masses. We also find that a fibrous tissue of recent formation constitutes the external layer of the acephalocysts and composite cystoidea, as well as the base and fundamental structure of cancerous growths in the kidneys.