544: ABSORPTION. 



This was frequently observed by Dalton in his experiments 

 on the thoracic duct, and he describes the jets as being 

 " like blood coming from a small artery when the circulation 

 is somewhat impeded." 1 This impulse is due to compression 

 of the thoracic duct as it passes under the arch of the 

 aorta. Its influence upon the general current of the 

 lymph and chyle is probably insignificant, but the fact 

 attracted the attention of Haller, who attached to it a 

 great deal more importance than it is now believed to 



Influence of the Movements of Respiration. While the 

 vis a tergo must be regarded as by far the most important 

 agent in the production of the lymphatic circulation, the 

 movements of fluids in the thoracic duct receive constant and 

 important aid from the respiratory acts. This fact has long 

 been recognized ; and in the works of Haller will be found a 

 full discussion of the influence of the diaphragm and the 

 movements of the thorax upon the circulation of chyle. 3 The 

 observations of Colin on this subject are most valuable, as 

 he was the first to successfully establish a fistula into the 

 thoracic duct in large animals. He always' found a marked 

 remittency in the flow of chyle from a fistula into the tho- 

 racic duct, which was absolutely synchronous with the move- 

 ments of respiration. With each act of expiration, the fluid 

 was forcibly ejected, and with inspiration, the flow was very 

 much diminished or even arrested. These impulses became 

 much more marked when respiration was interfered with and 

 the efforts became violent. The intermittency of the cur- 

 rent was sometimes'so decided, that the pulsations were re- 

 peated in a long elastic tube attached to the canula for the 



1 DALTON, Lectures on the Physiology of the Circulation. American Medical 

 Monthly and New York Review y December, 1860, p. 416. 



2 HALLER, Elementa Physiologies Corporis Humani, Bernss, 1765, tomus vii., 

 p. 237. 



3 Ibid. 



