ABSORPTION BY LACTEAL AND LYMPHATIC VESSELS. 



313 



FIG. 93. Different varieties of lymphatic glands. (Sappey.) 



It is evident, from the structure of the lymphatic glands, that they must materially 

 retard the passage of the lymph toward the great trunks; and it is well known in 

 pathology that morbid matters taken 

 up by the absorbents are frequently 

 arrested and retained in the nearest 

 glands. 



The function of the lymphatic 

 glands is very obscure. By some 

 they are supposed to have an im- 

 portant office in the elaboration of 

 the corpuscular elements of the 

 lymph and chyle; and it has been 

 observed that the lymph contained 

 in vessels which have passed through 

 no glands is relatively poor in cor- 

 puscles, while the large trunks and 

 the efferent vessels contain them in 

 large numbers. This single fact is 

 indefinite enough, as regards the 

 mode of formation of the lymph- 

 corpuscles, but it represents about 

 all that is actually known concern- 

 ing the function of the lymphatic 

 glands. 



In endeavoring to estimate the 

 share which the lacteal s and lym- 

 phatics have in the function of ab- 

 sorption, it becomes an important question to determine what principles these vessels 

 are capable of taking up, beside the fatty elements of the food, and how far, if at all, 

 they assist the blood-vessels in the absorption of the general products of digestion. 



Absorption of Albuminoids l)y the Lacteals. Comparative analyses of the lymph and 

 chyle always show in the latter fluid an excess of albuminoid matters. As we may rea- 

 sonably suppose that, during the intervals of digestion, the lacteals carry ordinary lymph 

 for, at this time, these vessels are filled with a colorless, transparent fluid, having the gen- 

 eral physical characters of lymph it is natural to infer* that the excess of nitrogenized 

 matters in the white chyle is due to absorption of albuminoids from the intestinal canal. 

 Mr. Lane collected the chyle from the lacteals of a donkey, seven and a half hours after 

 a full meal of oats and beans, and compared its composition with that of the lymph. The 

 analyses were made by Dr. Rees, who found that the chyle contained about three times 

 as much albumen and fibrin as the lymph. While by far the greater part of the products 

 of digestion of the albuminoids is absorbed by the blood-vessels, there can be no doubt 

 that a small portion is also taken up by the lacteals. 



Absorption of Glucose and Salts by the Lacteals. What has just been stated regard- 

 ing the absorption of albuminoids applies with equal force to saccharine matters and 

 the inorganic salts. Small quantities of sugar and sometimes lactic acid have been 

 detected in the chyle from the thoracic duct in the herbivora ; and the presence of sugar 

 in both the lymph and the chyle has been accurately determined by Colin. 



It is true that the products of the digestion of saccharine and amylaceous matters are 

 taken up mainly by the blood-vessels, but a small quantity is also absorbed by the lac- 

 teals. In the comparative analyses of the chyle and lymph by Dr. Rees, the proportion 

 of inorganic salts was found to be considerably greater in the chyle. The great excess 



