350 CHYLE, LYMPH, TRANSUDATES AND EXUDATES. 



causes an increase in the quantity of lymph. According to HEIDENHAIN, 

 on the contrary, a very considerable change in the pressure in the aorta 

 causes only a little change in the abundance of the lymph flow. The 

 quantity of lymph may be raised by powerfully active and passive move- 

 ments of the limbs (LESSER). Under the influence of curare, an increase 

 of the lymph secretion is observed (PASCHUTIN, LESSER 1 ), and the quan- 

 tity of solids in the lymph is also increased. 



The bodies inciting lymph flow, the so-called lymphagogues, are of 

 especially great interest, and they may, according to HEIDENHAIN, 2 be 

 divided into two different chief groups. The lymphagogues of the first 

 series extracts of crab-muscles, blood-leech, anodons, liver and intestine 

 of dogs, as well as peptone and egg albumin, strawberry extracts, meta- 

 bolic products of bacteria and others cause a greatly increased secre- 

 tion of lymph without raising the blood-pressure, and in this way the 

 blood-plasma becomes poorer in proteins and the lymph richer than 

 before. For the formation of this lymph, which HEIDENHAIN designates 

 blood-lymph, we must admit with him that a special secretory activity 

 of the capillary-wall endothelium exists. The lymphagogues of the second 

 series, such as sugar, urea, sodium chloride, and other salts, also cause 

 an abundant lymph formation. The blood, as well as the lymph, thereby 

 becomes richer in water. This increased amount of water depends, 

 according to HEIDENHAIN, upon an increased delivery of water by the 

 tissue-elements, and this lymph is chiefly tissue-lymph, in his opinion. 

 Diffusion is no doubt of great importance in the formation of this lymph , 

 but the secretory activity of the endothelium is also of importance, 

 at least for certain bodies, such as sugar. 



In the past, the formation of lymph was explained in a purely physical 

 way by the united action of filtration from the blood and the osmosis 

 between the blood and tissue-fluid. Later HEIDENHAIN and also HAM- 

 BURGER ascribed a special activity to the capillary endothelium, assum- 

 ing that they take part in the formation of lymph in a secretory manner. 

 The above-mentioned observations on the greater NaCl content in the 

 lymph as compared to the plasma as well as the regularly found higher 

 osmotic pressure of the lymph speak for such a view. 



According to ASHER and his collaborators (BARBERA, GIES and 

 BUSCH) the lymph is a product of the work of the organs. Its amount 

 is dependent upon an increased or diminished activity of the organs, 



1 Lesser, Arbeiten ars der physiol. Anstalt zu Leipzig, Jahrgang, 6; Paschutin, 

 ibid., 7. 



2 Heidenhain, Pfliiger's Arch., 49; Hamburger, Zeitschr. f. Biologic, 27 and 30. 

 See especially Ziegler's Beitr. zur Path. u. zur allg. Pathol., 14, 443; also Arch. f. 

 (Anat. u.) Physiol., 1895 and 1896. 



