ABSORPTION 3^9' 



of the substance m:.y be found in the lymph than in the blood. 

 Now, when a mixture of crystalloids and colloids is filtered through 

 a thin membrane, the percentage of crystalloids in the filtrate is 

 never, at most, greater than in the original liquid. And although 

 Cohnstein states that if time enough be allowed, the maximum con- 

 centration of sodium chloride in the lymph, after intravenous- 

 injection, becomes approximately the same as the maximum in the 

 blood, this fact loses its weight as an argument in favour of the 

 filtration hypothesis when we remember that, according to Asher, 

 all the solids of the lymph are markedly increased when even 

 small quantities of crystalloids are injected into the veins. Lazarus- 

 Barlow found, too, that the maximum outflow of lymph from 

 the thoracic duct does not occur at the time of maximum intravenous 

 pressure, and that in the great majority of his experiments the 

 injection of a concentrated solution of sodium chloride, glucose or 

 urea into a vein was followed, not by an initial diminution in the- 

 outflow of lymph (as might have been expected if the exchange 

 of water between the blood and the tissue spaces was regulated 

 solely by differences in osmotic pressure), but by an immediate 

 increase. 



So far we may say that while it has been made out that the 

 physical processes of filtration, osmosis and diffusion do play a part 

 in the passage of water and solids through the walls of the capillaries, 

 there is much which they leave unexplained, and which at present, 

 for the want of a more precise term, we must attribute to the secretory 

 activity of the endothelial cells. In addition, the cells of the tissues 

 in general, and particularly of the glands, appear to have a share in 

 the formation of the lymph. Asher and Barbera have found that 

 defibrinated lymph injected into the carotid artery of a dog produces- 

 marked effects on the circulation (Traube-Hering curves, paralysis 

 or in some cases stimulation of the vagus), and that these effects are 

 not produced by defibrinated blood. They conclude that the 

 common doctrine that lymph is simply a diluted blood-plasma is 

 erroneous, and attribute the toxic effects to products of the meta- 

 bolism of the tissues which have found their way into the lymph. To- 

 the lymph-glands they assign the function of transforming these toxic 

 bodies into harmless substances. Lymph, they say, so far from being 

 a mere filtrate or even a secretion from the blood, is formed by the 

 activity of the organs, and may actually be absorbed by the blood 

 from the tissue-spaces. In fact, according to their view the intra- 

 venous injection of lymphagogues, both crystalloid and colloid, only 

 causes an increased flow of lymph in so far as it leads to increased 

 glandular secretion. The injection of bile or albumose, for instance,, 

 is followed by a greatly increased secretion of bile, and with this 

 increase in the work of the liver is associated the production of a 

 greater quantity of lymph by its cells. While this is doubtless an 

 over-statement of the part played by the organs, we may safely 

 assume that they do make a contribution to the lymph ; their waste- 

 products pass into it, and possibly, as Koranyi suggests, by increasing 



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