HYPERJSMIA OF THE KIDNEY. 5 



3olor. In such cases, the pressure in the glomeruli hardly ever is suf- 

 ficient to occasion transudation of albumen, or to rupture the vessels, 

 and cause extravasation of blood into the Malpighian capsules. This 

 fact is in accordance with the results of physiological experimenta- 

 tion.. Ligation of the abdominal aorta below the origin of the renal 

 arteries, in spite of the increase of pressure which ensues in those arte- 

 ries, never results in albuminuria. 



A very different train of symptoms follows upon a moderate de 

 gree of obstructive engorgement of the kidney. Since, as we have 

 just shown, in almost every case of obstruction of the renal veins the 

 degree of tension within its arteries is very small, there is a diminution 

 instead of an increase of the secretion of urine. On the other hand, 

 the strain upon the capillaries becomes exceedingly severe, since they 

 cannot discharge their contents into the already overloaded veins until 

 the pressure within them exceeds that within the veins. Hence, not 

 only does the plasma of the blood readily escape from the capillaries 

 into the urinary tubuies, so that the scanty, concentrated, dark-colored 

 urine contains albumen, and the so-called fibrinous casts (or, more 

 properly speaking, exudation casts), but the delicate walls of the capil- 

 laries give -way before the strain, so that the urine is also full of blood- 

 corpuscles. According to the recent observations of Liebermeister, the 

 simultaneous appearance of blood and albumen is so usual in obstruc- 

 tive hypersemia of the kidney, that the appearance of albumen alone, 

 without a trace of blood, almost excludes the idea of simple engorge- 

 ment from the diagnosis, and indicates the existence of inflammation. 

 This fact in pathology, which may be verified in almost every case of 

 chronic disease of the heart, and traced through all its phases, agrees 

 with the results of physiological experiment. Albuminuria and haema- 

 turia are .the never-failing consequence of ligation of the renal veins, 

 or of the vena cava above their point of entrance. The escape of 

 plasma from the capillaries of the kidneys, in obstructive congestion, 

 into the uriniferous tubules is analogous to the extravasation from the 

 pulmonary capillaries into the air-vesicles, which occurs in engorgement 

 of the lungs, and which is there called hypostasis. The so-called 

 hypostatic pneumonia is quite as independent of genuine inflammatory 

 action as is the disorder of the kidney at present under consider- 

 ation. 



The form of renal hyperaemia which apparently proceeds from re- 

 laxation of the tissues of the kidney and consequent dilatation of its 

 capillaries, has no effect either in augmenting or diminishing the quan- 

 tity of urine secreted. It is attended, however, by a more or less pro- 

 fuse transudation of blood-plasma, as well as by a greater degree of 

 shedding, and probably too by a more active reproduction of the eel- 



