were present in the casts in considerable number, and also free in the Urine. A very marked case of this kind was that of a boy suffering from dropsy after scarlatina, whose Urine was loaded with pus casts and pus, at least with cells exhibiting the two or three central bodies upon the addition of acetic acid, and presenting all the characters of pus corpuscles.

Many large transparent waxy casts are observed scattered over the field, from which we should infer that the epithelium in many of the tubes had been destroyed, and the basement membrane rendered bare. At the same time it seems to me probable that at least in some cases these very large casts are derived from the straight portion of the uriniferous tube in the pyramid, where its diameter is very great. Although in many instances the tube in the cortical portion of the kidney is sufficiently dilated to receive such a cast, I much doubt if the dilatation of the channel at the base of the pyramid has proceeded to an extent sufficient to allow it to pass. That the cast is formed from a material which enters the tubes from the vessels surrounding it, and not only from the Malpighian capillaries, is rendered very probable by the circumstance, that new matter is often deposited upon the circumference of the cast as it passes down the tube. In this case we have a cast apparently within a transparent tube, a very good example of which is represented at b, and such specimens are not very uncommon. The mode of formation of casts, and their composition, will be fully considered elsewhere.

In the present case many of the tubes were denuded of their epithelium, while in others the epithelium was undergoing disintegration. In the latter instance the function of the tube as a secreting apparatus would be impaired, while in the former it would be altogether destroyed; and the structure of the organ so much altered that the hope of any permanent improvement would be slight.

PLATE XVIII.

CASTS. FATTY DEGENERATION OF THE KIDNEY.

Fig. 1. Casts containing oil from the Urine of a case of fatty degeneration of long standing.

Many cells of epithelium contain no oil.

Fig. 2. Cholesterine obtained from the fatty matter in casts separated from the Urine of a case of fatty degeneration.

Many globules, composed of oily non-crystallizable fat, are seen scattered in various parts of the field.

PLATE XVII.

CASTS. CHRONIC NEPHRITIS.

In Plate XVII several forms of granular casts are represented. In the upper part, about the centre of the page, is seen one cast containing cells of epithelium. These casts were obtained from the Urine of a man, age 34, who had been subject to chronic rheumatism for many years. The Urine contained a small quantity of albumen. The kidney disease had probably existed for several years, but its duration could not be accurately ascertained. Such casts are very commonly met with.

It will be observed that the casts in this specimen vary very much in diameter, some being scarcely more. than the 1-2000th of an inch, while others are as much as the 1-500th of an inch. The former come from exceedingly narrow tubes, or from tubes in which the epithelium is abnormally adherent, while the latter are derived from tubes denuded of epithelium.

In this case the kidney is probably much contracted, in the state which has been termed "Gouty kidney," by Dr. Todd, because the condition is very common in persons who have suffered for many years from gout.* In the majority of cases there can be no doubt that spiritdrinking lays the foundation of the mischief.

PLATE XVIII.

CASTS CONTAINING OIL.

In fatty degeneration of the kidney, the Urine is usually pale, and of low specific gravity. The deposit is light, bulky, and flocculent. It contains casts and cells containing oil globules. Although in other cases of disease

* Clinical Lectures on certain diseases of the Urinary Organs and on Dropsies, p. 69.