ABSORPTION OF WATER BY THE LACTEALS. 447 



tended. 1 In an experiment by Ernest Burdach, a dog was 

 deprived of food and drink for twenty-four hours, after which 

 he was allowed to drink water, and, in addition, half a pound 

 was injected into the stomach. The animal was killed a 

 half an hour after, and the thoracic duct was found engorged 

 with watery lymph, which contained a very small number of 

 lymph-corpuscles. 2 



In discussing the question of absorption by the blood- 

 vessels of the intestinal canal, we alluded to experiments 

 which showed that various poisonous substances introduced 

 into the intestines produced their characteristic effects upon 

 the system with great rapidity when the veins leading from 

 the part were intact, while no such effects followed when the 

 only avenue to the general system was through the lacteals. 

 During the time w^hen the question of exclusive absorption by 

 either the lacteals or the veins w T as so much agitated, a num- 

 ber of experiments were made by different physiologists to 

 show, on the one hand, that certain coloring matters and salts 

 were absorbed by the lacteals alone, and, on the other, that 

 these were absorbed only by the veins. These experiments have 

 lost much of their interest, now that the question of venous 

 absorption is definitively settled. "Without again discussing 

 these observations in detail, it may be stated as the general 

 results of experiments on this subject, that few, if any, of the 

 active poisons were found to be absorbed from the alimentary 

 canal, except by blood-vessels ; and when soluble coloring 

 matters, or salts which could be easily recognized, were 

 found in the lacteals or the thoracic duct, after they had been 

 introduced into the intestine, they penetrated in small quan- 

 tity and very slowly ; while it has been repeatedly found that 

 the same substances were taken up by the veins with great 

 rapidity and excreted, in many instances, by the urine. 



1 LEURET ET LASSAIGNE, Eecherches Physiologiques et Chimiques pour servir 

 d FHistoire de la Digestion, Paris, 1825, p. 197. 



2 G. F. BURDACH, TraitS de Physiologic, Paris, 1841, tome ix., p. 253 : addi- 

 tion by Ernest Burdach. 



