818 IMBIBITION AND EXHALATION. 



upper extremity and right side of the head and neck, and joins the 

 right subclavian vein at its junction with the corresponding jugular. 

 Thus nearly all the lymph from the external parts, and the whole 

 of that from the abdominal organs, passes, by the thoracic duct, 

 into the left subclavian vein. 



We already know that the lymphatic vessels are not to be re- 

 garded as the exclusive agents of absorption. On the contrary, 

 absorption takes place by the bloodvessels even more rapidly and 

 abundantly than by the lymphatics. Even the products of diges- 

 tion, including the chyle, are taken up from the intestine in large 

 proportion by the bloodvessels, and are only in part absorbed by 

 the lymphatics. But the main peculiarity of the lymphatic system 

 is that its vessels all pass in one direction, viz., from without inward, 

 and none from within outward. Consequently there is no circula- 

 tion of the lymph, strictly speaking, like that of the blood, but it 

 is all supplied by exudation and absorption from the tissues. 



The lymph has been obtained, in a state of purity, by various 

 experimenters, by introducing a canula into the thoracic duct, at 

 the root of the neck, or into large lymphatic trunks in other parts 

 of the body. It has been obtained by Rees from the lacteal vessels 

 and the lymphatics of the leg in the ass, by Colin from the lacteals 

 and thoracic duct of the ox, and from the lymphatics of the neck 

 in the horse. We have also obtained it, on several different occa- 

 sions, from the thoracic duct of the dog and of the goat. 



The analysis of these fluids shows a remarkable similarity in 

 constitution between them and the plasma of the blood. They 

 contain water, fibrin, albumen, fatty matters, and the usual saline 

 substances of the animal fluids. At the same time, the lymph is 

 very much poorer in albuminous ingredients than the blood. The 

 following is an analysis by Lassaigne, 1 of the fluid obtained from 



the thoracic duct of the cow : 



PARTS PER THOUSAND. 



Water 964.0 



Fibrin 0.9 



Albumen . 28.0 



Fat . 0.4 



Chloride of sodium 5.0 



Carbonic \ 



Phosphate and > of soda 1.2 



Sulphate J 



Phosphate of lime . . . . . . . 0.5 



1000.0 



Colin, Physiologie comparee des Animaux domestiques, vol. ii. p. 111. 



