The Digestion of Food 123 



The villi are adapted especially for the absorption of fat. 

 They dip like the tiniest fingers into the chyle, and the 

 minute particles of_fat_j:>ajis through their cellular cover- 

 ing and gain entrance to the lacteals. The milky material 

 sucked up by the lacteals is not in a proper condition to be 

 poured at once into the blood current. It is, as it were, in 

 too crude a state, and needs some special preparation. 



186, The Mesenteric Glands. The intestines are sus- 

 pended from the posterior wall of the abdomen by a double 

 fold of peritoneum, called the mesentery. That is, the 

 intestines are wrapped in a fold of the peritoneum some- 

 what as one would lie when slung in a hammock. 



In this membrane are some one hundred and fifty 

 nodules about the size of an almond, called mesenteric glands. 

 Now the lacteals join these glands and pour in their milky 

 contents which they have just absorbed to undergo some 

 important changes. It is not unlikely that the mesenteric 

 glands may intercept, like a filter, material which, if allowed 

 to enter the blood, would disturb the whole body. 



Having been acted upon by the mesenteric glands, and 

 passed through them, the chyle flows onward until it is 

 poured into the sac-like expansion of the lower end of the 

 thoracic duct, known as the receptaculum chyli. Into this 

 receptacle are poured not only the contents of the lacteals, 

 but also of the lymphatic vessels of the lower limbs. 

 1 187. The Thoracic Duct. This duct is a tube from fif- 

 teen to eighteen inches long, which passes upwards in front 

 of the spine to reach the base of the neck, where it opens 

 at the junction of the great veins on the left side of the 

 head with those of the left arm. Thus the thorackuduct 

 carries the nutritive material obtained from the 'iboa and 

 pours it into the blood current. It is to be remembered 

 that the lacteals are lymphatics lymphatics of the intestines. 



