110 t PHYSIOLOGY AT THE FARM. 



end in the left subclavian vein. The thoracic duct is made up 

 by the junction of five or six vessels, two or three of which 

 come out of the pelvis, two or three from the mesentery, and 

 one from the neighbourhood of the stomach and liver. The 

 tubes which conduct the chyle from the small intestines to the 

 mesenteric glands, and thence to the thoracic duct, are viewed 

 as being of precisely the same structure, and even as perform- 

 ing the same office, except after food has been taken, as the 

 common system of lymphatic vessels spread over nearly the 

 whole system. In short, as is commonly taught, the lacteal ves- 

 sels found between the laminse of the mesentery are in general 

 merely lymphatic absorbent vessels ; but when chyle is formed 

 in the intestines, then their office is to take up that chyle, or, 

 to speak more strictly, that incipient chyle, which the small 

 intestines afford. Again, the mesenteric glands, through which 

 the lacteal vessels are transmitted, are held to possess quite 

 the same structure as what belongs to the conglobate glands, 

 which are almost everywhere found in connection with the 

 lymphatic system. But of these hereafter. 



Liver. The liver, and sweetbread or pancreas, secrete each 

 a fluid which mingles with the digesting mass in the duo- 

 denum or highest part of the small intestines, so that these 

 organs are beyond doubt rightly named chylopoetic viscera. 

 It is not so certain that the spleen merits the same name. 

 It is, nevertheless, at present commonly ranked among the 

 chylopoetic organs. The reason now assigned for putting 

 the spleen in this place is, that its function, though not 

 perfectly ascertained, seems to be analogous to that of the 

 mesenteric glands, which unquestionably exert an important 

 effect on the nutritious fluid delivered up to the lacteal vessels 

 by the small intestines. The great glands throughout the 

 body, by an old arrangement, are called conglomerate such as 

 the liver, the pancreas, the parotid, the kidney and the spleen, 



