MICROSCOPICAL CHARACTERS OF THE CHYLE. 537 



The presence of sugar in the chyle was first mentioned 

 by Brande, who described it, however, rather indefinitely. 1 

 Glncose was distinctly recognized in the chyle by Trommer, 2 

 and its existence in many of the higher orders of animals has 

 since been fully established by Colin. 3 



Microscopical Characters of the Chyle. The milky ap- 

 pearance of the chyle as contrasted with the lymph is due to 

 the presence of an immense number of excessively minute fatty 

 granules. The liquid becomes much less opaque when treated 

 with ether, which dissolves many of the fatty particles. In fact, 

 the chyle of the thoracic duct is nothing more than lymph to 

 which an emulsion of fat in a liquid containing fibrin, albu- 

 men, and salts is temporarily added during the process of 

 intestinal absorption. The quantity of fatty granules in the 

 chyle varies considerably with the diet, and generally dimin- 

 ishes progressively from the smaller to the larger vessels, on 

 account of the constant admixture of lymph. The size of 

 the granules is pretty uniformly from ^jloQ ^ TYJO of an 

 inch.* They are much smaller and more uniform in size in 

 the lacteals than in the cavity of the intestine. Their con- 

 stitution is not constant ; and they are composed of the dif- 

 ferent varieties of fat which are taken as food, mixed to- 

 gether in variable proportions. This fact was well illustrated 

 in the experiments of Bouchardat and Sandras, who even 

 detected certain peculiar kinds of fat which had been fed to 

 dogs, in the contents of the lacteals and the thoracic duct. 5 



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

 Philosophical Transactions, London, 1812, p. 96. 



2 TROMMER, Unterscheidung von Gfummi, Dextrin, Traubenzwcker, und Rohr- 

 zucker. Annalen der Chemie und Pharmacie, Heidelberg, 1841, Bd. xxxix., 

 S. 360. 



3 COLIN, De V Origine du Sucre contenu dans le Chyle. Journal de la Physi- 

 ologic, Paris, 1858, tome i., p. 539 et seq. 



4 ROBIN, in NYSTEN'S Didionnaire de Medecine, Paris, 1865, article Chyle. 



6 BOUCHARDAT ET SANDRAS, Recherches sur la Digestion et V Assimilation des 

 Corps gras. Annuaire de Therapeutique, Paris, 1845, p. 242 et seq. 



