GLANDS. 453 



through the part of the peculiar fever poison ; and as the inflammation 

 of the skin terminates in an excessive development of epidermis, and a 

 desquamation of the surface, so the inflammation of the kidney excites 

 an increased development of the epithelium which lines the urinary 

 tubules : this material partly accumulates in and chokes up the tubes, 

 while part of it becomes washed out with the urine, and may be detected 

 in large quantities in that fluid by the aid of the microscope. 



" To the account then given, which I believe to be essentially correct, 

 subsequent observations enable me to make some important additions. 



" On a microscopical examination, the convoluted tubes are seen filled 

 in different degrees with nucleated cells, differing in no essential character 

 from those which line the tubes of the healthy gland. The chief differ- 

 ence between these cells, which are the product of inflammation, and those 

 which exist in health, consists in the former being generally of smaller 

 size and more opaque and dense in their texture. It is very interesting 

 and important to observe that, while the convoluted tubes are rendered 

 opaque by this accumulation of cells in their interior, the Malpighian 

 bodies are transparent and apparently quite healthy. The straight tubes 

 which form the pyramids also contain an increased number of cells ; but 

 there is reason to believe, that these cells are not formed in these portions 

 of the tubes, but that they are lodged there in their passage from the 

 convoluted through the straight tubes; the latter being merely ducts 

 leading into the pelvis of the kidney. Some of the tubes contain blood, 

 which has, doubtless, escaped from the gorged Malpighian vessels lying 

 within the dilated extremities of the tubes. There is no deposit outside 

 the tubes. The essential changes in the kidney are an increased ful- 

 ness of the blood-vessels, and an abundant development of epithelial 

 cells, differing slightly in general appearance, size, and consistence, from 

 the normal renal cells ; this increased cell- development occurring in those 

 portions of the urinary tubules, the office of which, as Mr. Bowman has 

 suggested, is to excrete the peculiar saline constituents of the urine, 

 while the Malpighian bodies, whose office is the separation of the water, 

 are unaffected. 



" The condition of the urine in these cases, is clearly indicative of the 

 changes occurring in the kidney. After the urine has been allowed to 

 stand for a short time, a sediment forms, and, on placing a portion of this 

 under the microscope, there may be seen blood corpuscles, with epithelial 

 cells in great numbers, partly free and partly entangled in cylindrical 

 fibrinous casts of the urinary tubes ; and, very commonly, numerous 

 crystals of lithic acid are present. As the disease subsides, which, under 

 proper treatment, it usually does in a few days, the blood, fibrinous casts, 

 and epithelial cells, diminish in quantity, and finally disappear ; but 

 traces of the casts and cells are still visible some days after the urine 

 has ceased to coagulate on the application of heat or nitric acid. 



" The casts and cells which appear in the urine, when the disease is sub- 

 siding, are such as have remained some time in the urinary tubes before 



