294 DISTURBANCES OF CIRCULATION 



will be found to contain endotlieliotoxins, so that when this serum 

 is injected subcutaneously into a susceptible animal, large local hemor- 

 rhages result; if injected into the peritoneal cavity, there results 

 marked desquamation of the endotlielial cells, which soon undergo de- 

 generative changes (Ricketts).^^ It is quite probable that the bac- 

 terial poisons that cause marked hemorrhagic manifestations likewise 

 contain endotlieliotoxins, although tliis matter does not seem to have 

 been investigated. 



Even hemorrhage by diapcdesis seems to be due to, or at least 

 associated with, chemical changes in the capillary walls, for Arnold ^* 

 found that when capillaries from M^hich diapedesis had occurred 

 were stained by silver nitrate, dark areas were found between the 

 endothelial cells. As silver nitrate is a stain for chlorides, and dark- 

 ens intercellular substance because it is rich in sodium chloride 

 (Macallum), it is probable that there is an increase in the amount 

 or a difference in the method of combination of the chlorides of the 

 cement substance between the endothelial cells at the places where 

 red corpuscles escape. ]\I. H. Fischer ^^ suggests that diapedesis re- 

 sults from a change in the endothelial cells, which under the influence 

 of acids or other agents of metabolic origin become excessively hydro- 

 philic, swell up, and become so softened that corpuscles may pass di- 

 rectly through the cell, just as a drop of mercury can pass through 

 a sufficiently soft jelly without leaving a hole in the jelly. 



Hemorrhage in cachetic conditions is often ascribed to changes 

 in the vessel-walls due to malnutrition, but it is difficult to imagine 

 capillary walls suffering from lack of nourishment, even with the 

 poorest of blood, and it seems more probable that the hemorrhages are 

 due, even in cachexia, to chemical constituents of the blood that in- 

 jure the endothelium. Hemorrhages that follow re-establishment of 

 the circulation after complete occlusion, however, may be the result 

 of asphyxial changes in the capillary walls, presumably colloidal swell- 

 ing of the cells. 



After severe hemorrhages the blood shows a decrease in specific 

 gravity and viscosity, an increase in surface tension and electrical 

 resistance, and either increase or decrease of the freezing-point de- 

 pression, all these changes being transient if the individual is other- 

 wise normal.-" (See also Secondary Anemia.) There is a rapid 

 absorption of fluid from the tissues and tissue spaces, resulting in a 

 dilution of protein and formed elements, but not of salts. There is 

 ?aid to be a decreased permeability of vessels, resulting in reduced 

 exudative processes.^ "^ The proportion of the several blood proteins 



17 Trans. Chicago Path. Soc, 1902 (5), 181. 



18 Virehow's Arch., 1S75 (62), 157. 



m "Nophriiis," New ^'ork, 1012, p. 78. 

 2"01iva, Folia cliiiicii, 1!»12 C?), 21:^ 

 »«ii.Liiitlil('ii, M.'d. Klin.. 1913 (9), 1713. 



