CHAPTER XI. 

 Tab. XXII. — package of the viscera, and mesentery. 



Fig. 1. In this plate the parietes of the chest and abdomen, 

 with the omentum, are removed to show the visc^era in situ ; 

 a, the heart; b, the aorta; c, the descending vena cava; d, the 

 lungs divided by the mediastinum into two portions ; three 

 lobes belong to the right, and two to the left portion of the 

 lungs ; e, the diaphragm, or that muscle which separates the 

 thorax-from the abdomen ; /, the liver ; g, the gall-bladder ; h, 

 the stomach ; i, the spleen ; k, the large intestines ; Z, the small 

 intestines ; m, the bladder. 



The viscera of the thorax and abdomen, i. e. the viscera of 

 organic life, are irregularly disposed. The agents of volition 

 are double, but the instrmiients of involuntary motion, namely, 

 the interior life, are single, and at least are ii^-egular in their 

 form. 



The several viscera are correctly described in the Theol- 

 ogy, and sufficient is said for the purposes for which they are 

 introduced. To the supposed use of the spleen only an objec- 

 tion must be taken : various hypotheses have been entertain- 

 ed as to its office, but none are conclusive ; the most probable 

 is, that it is a source of supply of blood for furnishing the 

 gastric secretion, or that the blood undergoes some important 

 change in it. 



Fig. 2. The mesentery. This membrane is formed by a re- 

 flection of the periton(Eum from each side of the vertebrae ; it 

 connects the intestines loosely to the spine, to allow them a 

 certain degree of motion, yet retains them in their places ; 

 and furnishes their exterior covering. Between the laminae 

 of, a, the mesentery, are received the glands, vessels, and neryc*; 

 and its extent admits of a proper distribution of each. 



