350 EDEMA 



and in tuben-iilous jileuritis 0.526°. This indicates that the osmotic 

 concentration of the fiuid is highest in renal dropsy, and supports the 

 belief that here and in cardiac dropsy osmotic pressure plays a more 

 important part than it does in inflannnatory exudation. Of the 

 crystalloids that cause accumulation of fiuid in the tissues, sodium 

 i-hloride seems to be the most important. 



Retention of Chlorides in Edema. :^'' — From the investigations made l).v numer- 

 ous clinicians, especially the French, it appears that — (1) in nephritis with 

 edema a retention of sodium chloride frequently occurs; (2) that elimination 

 of the clilorides is often increased durino; periods of improvement of the edema: 

 (3) that a reduction of the amount of clilorides in the diet sometimes causes a 

 great improvement in the edema, while administration of chlorides may make 

 the edema mucli worse. There are, however, observations that also indicate that 

 chloride retention does not account for many cases of renal dropsy, for com- 

 monly the above-mentioned conditions are not fulfilled. st^a. Nevertheless, it cannot 

 be denied that chloride retention is sometimes an important causative factor in 

 the edema of parenchymatous nephritis. 37 If the retained chlorides obeyed the 

 ordinary laws of diffusion, we should expect them to become distriluited alike in 

 the bIoi)d and tissues, so that they would merely cause an equal increase in the 

 lluids of the blood and of t!ie tissues; that is to say, tliere would be an hydremic 

 plethora due to retention of water in the body by the accinnulating chlorides. 

 But, according to a number of observers, there is a specific retention in tlie 

 tissues, which Strauss calls "historetention," and which explains the local edema. 

 The way in which the historetention is produced is, however, not understood, and 

 not all observers accept this hypotliesis. If chlorides do bear a causative rela- 

 tion to edema, the predilection of the sulicutaneous tissues for edematous accumu- 

 lations may be explained by the observation that when salt is given to an animal 

 an undue proportion (28-77 per cent.) accumulates in the skin.sTa In many 

 conditions other than nepliritis, there is also a cliloride retention {e. g., pneu- 

 monia, cardiac incompetence, sepsis, typlioid), and the edemas observed in these 

 diseases may possibly depend upon cliloride retention, as many Frencli authors 

 suggest. Rumpf, indeed, often found more chlorides in edematous lluids of non- 

 nephritic origin than in nephritic edema.s'^b Fischer holds that the retention 

 of chlorides in edema is secondary and not primary, for he foimd that tissues 

 made to take up more water through acidification, also take up an increased 

 amount of chlorides. 



'^ Inflammatory Edema. — Although here the alterations in the cap- 

 illary walls play an essential role, as shown by the protein-rich na- 

 ture of the exudates, yet most of the other factors are added. In- 

 creased blood pressure is prominent ; lymph outflow is impeded by 

 plugging of the lymphatic channels by clots and leucocytes, and by 

 pressure on the outside ; there is, undoubtedly, an excessive forma- 

 tion of metabolic products in the tissues, to cause exosmosis, and the 



3« Literature, resumf" bv \Yidal and Javal, Jour. Phvsiol. et Pathol., 1003 (5), 

 1107 and 1123; Rumpf, Miinch. med. Woch., 1005 (52), 303. Review in Albu 

 and Neuberg's "Mineralstoffweclisei," Berlin. IflOO, pp. 171-178; Georgopulus. 

 Zeit. klin. Med., !!)()() (tlO), 411; Cliristian, Boston Med. and Surg. Jour., 1008 

 (158), 416; Palmer, Arcli. Int. Med.. I'M") (15), 329. 



3Ga See Blooker, Deut. Arcli. kliii. y\vd.. liM)!! ( Od ) . SO; Fischer, "(iMlcnia and 

 Nephritis." 



37 See Borcbardt, Deut. med. Woch., 1012 (38), 1723. 



37a Scliade. Zeit. exp. Patli. u. 'Ilier.. 1013 (14), 1. Also gives an interesting 

 discussion of the relation of the skin to edema. 



37b Breitmann ( Zentr. inn. Med., 1013 (34), 033) describes under tlic name of 

 "soda dropsy" a form of edema which results from excessive administration of 

 sodium bicarl)onate to correct acidosis in diabetes. 



