Page:Manual of pathological anatomy (IA manualofpatholog00jone).pdf/66

50 CONSEQUENCES OF CONGESTION. found in the peritoneal cavity after death, in casos of ascites, and the same are also seen occasionally in the fluid evacuated by para- centesis, We hayoalso scen blood-globules so uniformly dispersed through the ftuid that there could be no doubt that they had escaped from the congested sub-serous capillaries, and were not accidentally mingled with tho cffusion, The same products of con- gestion also occur in the urine when obstructive disease of the heart throws back the blood on the renal veins. The secretion is albuminous, contains fibrinous casts of the tubes and blood- globules. Decided hemorrhage may also oceur, as the result of extreme congestion, which may be dependent either upon yenous obstruction or upon an atonic state of the vessels. Melmna, or hemorrhage from the bowels, is an instance of the first, passive monorrhagia and epistaxis of the latter.

Textural Changes resulting from Congestion.—It is a remarkable and instructive fact that congestion of parts neyer seems in the end to occasion hypertrophy; or, if this should appear to have taken place, closer examination proves that rather the reverse is the ease; that the hypertrophy is what Rokitansky calls unreal. Enlargement of organs may indecd be a consequence of yenous congestion, if it has not continued long enough seriously to inter- fere with their nutrition; and is especially seen in very vascular

arts, where the mere dilatation of capillaries and yeins is

loubtless one of the main causes of enlargement. The spleen, for instance, is usally found enlarged in eases of cirrhosis of the liver, where tho portal vein is obstructed; and obstructive disease of the heart produces at a cortain stage of the disease enlargement of the liver and kidneys. In tho latter cases, however, certainly, and probably in the first the enlargement is only temporary, and the impaired nutrition which results from an inadequate supply of proper blood leads to a condition of atrophy, the external appear- ance of which will yary according to the organ involved. ‘In the skin there will be ulceration ; in solid organs, such as the liver and kidney, there will be what is called fibroid degeneration, or better fibroid substitution; that is to say, a replacement of the proper secreting structure by a certain form of connective tissue ; so that the organ will be in most cases actually smaller; at all events wasted, so far as its proper structure is concerned.

We have already pointed out the impairment of vital power which congestion occasions, and the causes inducing it, which seem to afford an adequate explanation of the non-tendency to growth and development which is observed both in the affected part itself and in its interstitial effusions. The following sentence from Mr, Simon’s lecture recozuizes and similarly explains the same fact: “Tt is true that much blood is contained in the affected tissue ; but it is blood that has insufficient means of renewing itself; and from its long detention in the part it acquires in an extreme degree, the character of venous blood. Thus, as regards mere bulk of blood, the part is over-supplied. but, im respect of the quulity of blood, it �