Local Aiuviiiia: IJa-uiorrha^e. II9 



and with the existing diminution of nutritive and secretory sub- 

 stances disturbances of nutrition and diminution of functional 

 aoility must ensue. In addition the products of previous meta- 

 bolic activity necessarily remain in the anaemic tissue and may act 

 unfavorably upon it. According to the grade of oxygen depriva- 

 tion, need for nutrition and rapidity of metabolism in the affected 

 structure there must sooner or later result a gradual death of the 

 anaemic part, because of the absence of blood. It should be kept 

 in mind, too, that the integrity of the endothelial lining of the 

 blood vessels depends upon the continuous flow of blood through 

 the vessel and that these cells gradually degenerate and become 

 permeable when the anaemia is complete. Should the blood again 

 flow through such capillaries which have been empty for perhaps 

 twenty-four hours it readily escapes through their walls, with con- 

 sequent haemorrhagic infiltration of the surrounding tissues. 

 (After interruption for as much as two hours the renal epithelial 

 cells become necrotic and consequently the renal function becomes 

 checked or ceases entirely.) Suspension of activity in vital organs 

 because of anaemia is a matter of extreme gravity. Cerebral 

 anaemia is quickly followed by unconsciousness ; and because of 

 degeneration of the central nervous tissue, even after but brief 

 periods of anaemia, this condition in the brain and spinal cord is 

 likely to give rise to destruction of the ganglion cells and focal 

 lesions with symptoms of paralysis. Complete anaemia of the myo- 

 cardium necessarily causes cessation of the heart's action. 



Other parts of the system, as the skin and muscles, are less sen- 

 sitive to the effects of anaemia ; their tissue may withstand the 

 condition for some hours, as may readily be appreciated by the 

 practice of artificially causing an anaemia in surgical operations by 

 means of the Esmarch's elastic bandages. In case of such resistant 

 parts, if the cause of the anaemia be eliminated the results may be 

 but transient or only partial, as in case of the anaemia of cramps 

 (spastic anaemia) or anaemia caused by external pressure. Ob- 

 struction of an artery, and more particularly the anaemia resulting 

 therefrom, may be corrected if the blood supply can be quickly re- 

 established through the anastomotic vessels (so-called collateral 

 paths). 



Loss of Blood; Haemorrhage. 



The escape of blood from the vessels into the tissue spaces, 

 bodv cavities or to the free surfaces of the bodv is known as 



