6 MODE OF PRODUCTION 



from diminished contractile power of the capillaries, 

 the same circumstance occurs spontaneously. 



In the disease called phlegmasia dolens, or that in 

 which there is a pale inelastic swelling of the leg, 

 arising from the obstruction of the femoral vein by 

 phlebitis, it may be presumed that the congestion of 

 the capillaries has been sufficient to cause albumi- 

 nous effusion into the cellular tissue. 



In certain organs of the body, which are liable to 

 sudden and great increase in the quantity of blood 

 sent to them, nature seems to have taken precautions 

 and made arrangements in their structure to prevent 

 this effect of congestion from resulting. 



Thus, in erectile tissue, the veins are large and 

 numerous, and form either plexuses or cells, into 

 which the excess of blood is received, and from 

 which, when the inordinate action of the arteries 

 has ceased, it gradually flows out, albuminous ef- 

 fusion being also prevented by the dense fibrous 

 tissue surrounding the vessels. In the spleen, a 

 somewhat similar disposition occurs, probably for 

 the same reason. 



The differences observed in their natural and 

 morbid secretions between the serous and mucous 

 membranes are also worthy of consideration, as bear- 

 ing in some measure on this point. 



The structure of the former membranes is very 

 dense, their vessels are so minute as not to admit the 

 entrance of the red particles of the blood, and a fine 

 vapour is the only transudation through their coats. 

 When, from increased arterial action, a state of acute 

 congestion is produced, it is evident that each vessel. 



