xiv THE LYMPH 527 



centres on the formation of lymph. On cutting the medulla 

 oblongata, or blocking its blood -supply in dogs by means of 

 artificial emboli, he noted a rise in the amount, and fall in the 

 concentration, of the lymph flowing from the thoracic duct. Under 

 these conditions, also, the intravenous injection of curare, bile, and 

 urea determined an increase of lymph, which with the two first 

 substances becomes more concentrated, with urea, on the contrary, 

 less concentrated than the normal. Peptone in dogs with a 

 paralysed vasomotor centre exhibits a much less intense lympha- 

 gogic action than the normal. The lymphagogic action of caffein 

 disappears entirely, while sodium chloride preserves its action of 

 lymphagogic potency. 



VI. All that we have been considering refers exclusively to 

 what Heidenhain calls blood-lymph. We must now examine the so- 

 called tissue-lymph, and the organs which more particularly concur 

 in forming and modifying it. 



We have seen that lymph cannot be considered as a simple 

 residue of blood plasma, unappropriated by the tissue cells. Part, 

 at least, of the chemical products formed by these cells is poured 

 into the lymph spaces, and modifies and renders more complex 

 the lymph turned out of the blood capillaries. Theoretically, it is 

 undeniable that the lymph from different organs and tissues must 

 have a different composition. The work of Heidenhain, completed 

 and partly rectified by Starling, gives confirmatory evidence of 

 this. The lymph coming from the limbs regularly contains a 

 lower percentage of proteins than that from the intestine, and the 

 latter contains a larger amount of proteins than that from the 

 liver. It appears improbable that this difference depends as 

 supposed by Starling on the normal differences in permeability 

 of the blood capillaries in different areas. It is more logical to 

 admit that the three kinds of lymphs are dissimilar because, coming 

 from different tissues, they are modified in various ways by the 

 elaboration products of the same. 



The quantity of lymph, again as was justly observed by 

 Asher and Barbera may and must depend on the degree of 

 functional activity of the tissue cells. When the work of an organ 

 increases, the quantity of dissimilation products increases also, and 

 with it the quantity of lymph poured into the lymphatic spaces ; 

 on the other hand, this increase in the products eliminated by the 

 organ may, since it modifies the difference in osmotic pressure 

 between blood and lymph, determine an increase in the transudation 

 of plasma through the blood capillaries. Experimental data in 

 support of this theory are not wanting. Stimulation of the lingual 

 branch of the trigeminus causes a marked accumulation of lymph, 

 with consequent oedema in the corresponding half of the tongue. 

 This phenomenon was first observed by Ostroumoff, and was 

 subsequently confirmed and developed by Marcacci (1883). It i& 



