CHAPTEE X 



THE LYMPH AND ITS MOVEMENTS 



The lymph or ff tissue fluid " is the medium in which the cells of the 

 body live. In part it is imbibed into the living substance itself, and in part 

 is collected in otherwise empty spaces about and between the cells. The 

 entire body is permeated throughout with such spaces which are of the greatest 

 variety of forms : clefts, minute canals, sheaths, sacs, etc., and exhibit the 

 greatest possible difference in size. Some, such as the so-called serous sacs, 

 like the peritoneum, the pleura, the pericardium, the serous sacs surrounding 

 the organs of the central nervous system, etc., are enormously large, while 

 others can only be detected with high magnification. All these fluid-filled 

 spaces, of whatever kind, communicate 1 with the lymph vessels, and through 

 them with the blood system. 



The lymph comes from the blood and is conveyed again by the lymph 

 vessels to the blood. Besides, certain constituents of the lymph are taken up 

 directly into the blood vessels through the permeable walls of the capillaries. 



From the blood the lymph receives all the substances necessary for the 

 life of the cells; from the cells it receives the products formed in their own 

 life processes, both those which arise as a result of the dissimilatory activities 

 and those which are formed by synthetic processes in one organ or another 

 for use in still other organs. It follows that the lymph in the different 

 organs must be of different composition, since on the one hand the require- 

 ments of the different organs are different both qualitatively and quantita- 

 tively, and on the other the products of assimilation and dissimilation are 

 different. 



However, we have at present no complete analyses of the lymph in the 

 different organs, nor of the lymph flowing from the different organs; our 

 knowledge is limited almost entirely to the composition of the mixed lymph 

 to be obtained from the thoracic duct. 



1. THE CHEMICAL PROPERTIES OF THE LYMPH 



The lymph, as one of the discoverers of the lymph system (Olaus Eud- 

 beck, 1673) remarked, is a water-clear liquid of salty taste, which coagulates 

 spontaneously. Our knowledge is at this time but little more extensive. 



The lymph contains scattered leucocytes. Its chemical composition agrees 

 qualitatively with that of the blood plasma but quantitatively differs from it 



According to the recent researches of McCallum and Sabin, the lymph vessels are 

 closed tubes like the capillaries. If so, we must think of the tissue-spaces and serous 

 cavities as separated by thin walls from the real lymph channels. ED. 



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