520 ABSOKPTION. 



corpuscles are identical with tlie leucocytes of the blood, and 

 the red disks frequently find their way from the blood-vessels 

 into the lymphatics. 



In addition to the constituents of the lymph ordinarily 

 given, the presence of glucose, and more lately, the existence 

 of a certain proportion of urea, have been demonstrated in 

 this fluid. Brande, in 1812, noted the presence of sugar in the 

 chyle, but not in the lymph. 1 It has since been demonstrated, 

 however, in the lymph, by Gubler and Quevenne, 2 Poiseuille 

 and Lefort, 3 Colin, 4 and others. Poiseuille and Lefort found 

 that the proportion of sugar was always greater in the lymph 

 than in the chyle. The recent researches of Colin show that 

 the difference between the proportion of this substance in the 

 lymph and in the chyle is not very great, and its quantity 

 does not vary very considerably in different classes of ani- 

 mals. His observations were made upon horses, oxen, and 

 dogs, and the proportion of sugar varied between 1*02 and 

 1*58 parts per 1,000. 5 It has not been ascertained how the 

 sugar contained in the lymph takes its origin, and its func- 

 tion in this situation is equally obscure. 



The presence of urea in considerable quantity in both the 

 chyle and the lymph has been determined by Wurtz ; 6 and 

 it is thought by Bernard that the lymph is the principal 



1 BRANDE, Chemical Researches on the Blood and some other Animal Fluids. 

 Philosophical Transactions, London, 1812, p. 96. 



Brande noticed crystals of what he supposed to be sugar of milk in the alco- 

 holic extract of the fluid taken from the thoracic duct four hours after feeding. 



2 GUBLER ET QUEVENNE, op. cit. Gazette Medicale de Paris, 1854, p. 454. 

 These observers, while admitting that the existence of sugar in the lymph is ren- 

 dered exceedingly probable as the extract reduced a copper solution did not 

 assume to have positively demonstrated its existence. 



3 POISEUILLE ET LEFORT, De V Existence du Glycose dans V Organisme Animal. 

 Comptes Rendus, Paris, 1858, tome xlvi., p. 567, and Note supplementaire, Ibid., 

 p. 678. 



4 COLIN, De I 1 Origine du Sucre contenu dans le Chyle. Journal de la Phy- 

 siologie, Paris, 1858, tome i., p. 539 etseq. 



5 Loc. cit., p. 544. 



6 BERARD, Formation Physiologique du Sucre dans V Economic Animate.' 



