LESSON 62.] NUTRITION IN MAN. 213 



LESSON LXII. 



NUTRITION IN MAN, CONTINUED. 



928. When it reaches the intestine, the chyme is subject to new 

 influences ; the Liver supplies its bile, and the pancreas (or sweet- 

 bread) the pancreatic juice, and by their means the chyme becomes 

 changed into chyle, or new blood, which is to circulate throughout 

 the body, to renew wasted material, and to promote growth. 



929. When formed, the chyle is white and milk-like, and is asso- 

 ciated with innutritious materials ; from these it is separated, firstly, 

 in the duodenum, and what then escapes is subsequently constantly 

 being separated throughout the tract of the small intestines. 



930. But the chyle is not blood ; it does not yet possess the ne- 

 cessary requirements of that fluid it has no life ; it wants, in fact, 

 another element, oxygen, and must go to the lungs to obtain it. 

 For this purpose the villi of the small intestines are provided with 

 certain tubes, or canals, called lacteals, from lacta, milk, and it is 

 their duty to take up or remove the chyle, still white, and convey it 

 upwards to a reservoir in the chest called the thoracic duct ; thence 

 to the heart, and finally to the lungs, from which latter organ it is re- 

 turned to the other side of the heart (the left side), of a beautiful 

 bright vermilion color, endowed with all the properties of new blood, 

 and forthwith to be distributed by the arteries to all parts of the 

 body, for the purposes of nutrition. 



931. The injected preparation of the mucous membrane of the 

 stomach of the human subject (Fig. 336) 



is a magnificent spectacle ! Here we 

 have a dense arrangement of honeycomb- 

 like cells, the walls of which are formed, 

 not of a single capillary as we have hith- 

 erto seen, but a plexus of very delicate 

 vessels. This particular arrangement is 

 only met with in the mucous membranes 

 of man, and the monkey ; in all other ani- 



, -i -if ii n n Mucous membrane of human 



mals single vessels form the cell walls ; stomach. 



by this sole characteristic the human stomach (or monkey) may be 



readily known. 



932. The commencement of the duodenum, soon after its junc- 

 tion with the pylorus, abounds in glands, known as "Brunner's 

 glands," from their supposed discoverer ; in truth, however, these, in 



