506 ABSORPTION. 



the circulating fluid. The influence of pressure, which is so 

 often observed in the dropsies which result from venous ob- 

 struction, was noted nearly two hundred years ago by Lower, 

 who observed that there was a serous effusion under the 

 skin of the face of a dog after the jugular veins had been 

 tied. 1 This fact is too well established to need further illus- 

 tration. 



The influence of the constitution of the blood upon transu- 

 dation is very interesting. The exosmotic properties of albu- 

 men are so slight, that there is usually but a very small amount 

 of transudation through any of the vessels, and the fluid thus 

 effused contains but a minute quantity of albumen ; but if the 

 density of the blood be greatly diminished, and especially if it 

 become impoverished in albumen, transudation may become 

 so active as to produce general dropsy. The deficiency 

 in albumen in the blood of persons suffering from general 

 dropsy was observed by Bostock, who, at the instance of Dr. 

 Bright, made a number of examinations of the blood from 

 patients suffering from what is now known as renal dropsy. 

 " In the serum of these patients the proportion of albumen 

 was found to be less than in health." 2 This fact has since 

 been noted by other observers, particularly by Becquerel 

 and Kodier, who made a large number of observations show- 

 ing the influence of a deficiency of albumen in the blood 

 upon transudation. 3 These facts have a pathological rather 

 than a physiological bearing, but they illustrate the influence 

 of the albumen of the blood upon normal transudation by 

 exosmosis. 



1 LOWER, Tradatus de Corde, item de Motu et Colore Sanguinis, ct Cliyli in 

 eum Transitu, Amstalodami, 1669, p. 124. 



8 BOSTOCK, An Elementary System of Physiology, London, 182*7, p. 411. 



3 BECQUEREL ET RODIER, De TAnemis par Diminution de Proportion de VAl- 

 bumine du Sang, et des Hydropsies qui en sont la Consequence. Extrait de la Ga- 

 zette Medicate de Paris, 1850. 



