8 DISEASES OF THE KIDNEY. 



loses its color, beginning at the middle, and becomes converted iiito a 

 yellow, caseous mass, or else breaks down, forming a renal abscess, 

 with yellow puruloid contents, which at first consist of detritus alone, 

 but afterward are mixed with pus. Finally, these caseous or purulent 

 masses also are reabsorbed, and at the site of the former infarction 

 there is left a cicatricial contraction. 



The seat of renal apoplexy is generally the medullary portion of 

 the kidney. Collections, of varying size, form in the lacerated paren- 

 chyma, their contents consisting partly of clotted blood, and in part 

 of crushed and broken-down debris of the tubules. It would seem 

 that the contents, both of apoplectic extravasations and of haemor- 

 rhagic infarctions, may undergo fatty degeneration and absorption, and 

 that recovery may take place, leaving a depressed cicatrix. Part of 

 the blood effused into the tubules coagulates, forming cylinders, which 

 are densely studded with blood-corpuscles. Sometimes we find pig- 

 ment in the tubules and Malpighian capsules, as the residue of some 

 former extravasation of blood. 



SYMPTOMS AND COURSE. The occurrence of renal haemorrhage 

 does not become recognizable unless the blood be effused into the 

 tubules, and discharged with the urine. Hence it not unfrequently 

 happens, in post-mortem examinations, that haemorrhagic infarctions 

 and apoplectic extravasations are discovered, which were quite undis- 

 coverable during life, because the blood did not enter the uriniferous 

 tubules. If the amount of blood mingled with the urine be very small, 

 the color of the latter is a peculiar dirty red when viewed by reflected 

 light, while by transmitted light it is a pure red of greater or less 

 depth. After standing for some time, a somewhat characteristic, 

 slightly flocculent, brownish sediment is precipitated. When urine 

 containing blood is exposed to the action of heat and nitric acid, the 

 albumen of the serum of the blood coagulates. If the sediment be 

 examined microscopically, blood-corpuscles are found, some of which 

 are well preserved, while others are somewhat altered. There are also 

 the casts above described, studded with blood-corpuscles, which are 

 peculiarly characteristic of renal haemorrhage. I strongly recommend 

 Heller's test for blood as very simple and convenient, and by means 

 of which the faintest trace of blood may be discovered. Heat the 

 urine, then add caustic potash and heat anew. The phosphates arc 

 thus precipitated, taking with them the coloring matter of the blood, 

 which imparts a dirty yellowish-red color to the sediment viewed by 

 reflected light, and, when seen by transmitted light, gives a splen- 

 did blood-red color. Neither the coloring matter of the blood nor 

 tlmt of the bile is precipitated with the phosphates, so that color- 

 ation of urine which shows this reaction cannot be ascribed to the 

 of the latter pigments. When the quantity of blood in the 



