FORMATION OF LYMPH 277 



1234 



Water 939.9 934.8 957.6 955.4 



Solids 60.1 65.2 42.4 44.6 



Fibrin 0.5 0.6 0.4 2.2 



Albumin 42.7 42.8 34.7) 



Fat, cholesterin, lecithin . . 3.8 9.2 . . \ 35.0 



Extractive bodies 5.7 4.4 . . j 



Salts ; . 7.3 8.2 7.2 7.5 



1 and 2 are analyses of lymph from the thigh of a woman, 3 is from the 

 contents of sac-like dilated vessels of the spermatic cord, 4 is lymph from the 

 neck of a colt. 



Chyle differs from lymph chiefly in the presence of large quantities of 

 fat ; during starvation the lymph and the chyle are of practically the 

 same composition. 



Normal lymph contains much less fibrinogen than does the blood 

 plasma, and hence coagulates slowly. Lipase and other enzymes have 

 been found in the lymph, as in the plasma. The products of tissue 

 metabolism added to the lymph by the cells may render it toxic (Asher 

 and Barbera 1 ). Under pathological conditions the lymph may be 

 greatly altered, becoming poorer in solids under some conditions of 

 edema, and becoming rich in proteids and blood-corpuscles under inflam- 

 matory conditions, until it partakes of the characteristics of an inflam- 

 matory exudate (see analyses of transudates and exudates). 



FORMATION OF LYMPH 2 



Filtration Theory. The simplest possible conception of 

 lymph formation is that it is simply the result of filtration of 

 the liquid constituents of the blood through the capillary walls 

 under the influence of the blood pressure. This "filtration 

 theory " was supported originally by Ludwig, and it was a prom- 

 inent factor in the early applications of mechanical principles 

 to biological processes. In support of this theory were advanced 

 the results of numerous experiments in which it was shown that 

 increasing the blood pressure by means of ligating the veins, or 

 by causing arterial dilatation, resulted in an increase of the 

 lymph flowing out of the lymph-vessels of the part. The 

 experimental results were not always favorable to the theory, 

 however, particularly in the experiments in which blood pres- 

 sure was raised by arterial dilatation ; often the flow of lymph 

 was little increased, even when the arterial flow and pressure 

 were greatly increased. Furthermore, as Leonard Hill 3 has 

 urged, there is reason for questioning the existence of such a 

 thing as a " filtration pressure " in organs or tissues provided 

 with a capsule, since within this capsule all structures must be 



1 Zeit. f. Biol., 1898 (36), 154. 



2 See review by Asher, Biochem. Centralblatt,1905 (4), 1. 



3 Biochemical Journal, 1906 (1), 55. 



