92 PHYSIOLOGY OF THE CIRCULATION. 



And as this power was by Magendie himself con- 

 sidered as but one of the probable causes of vascular 

 absorption*, it still remains to discover what other 

 physical conditions assist in the performance of this 

 function. 



There is another view of absorption, which as it, 

 in name at least, bears some resemblance to that 

 which I shall presently advance, requires a moment's 

 examination. I allude to the opinion of the late Sir 

 D. Barry. The experiments of this gentleman prove 

 very satisfactorily, that during each act of inspiration 

 there is a rush of venous blood into the imperfect 

 vacuum then formed within the thoracic cavity. On 

 introducing a long glass tube into the interior of 

 certain large veins, he also found that a coloured 

 liquid, into which the lower end of the glass tube 

 dipped, ascended in the latter to the height of several 

 inches during each inspiration, and fell during the 

 opposite act of expiration. 



This ascent of the coloured fluid he conceived to 

 be an act of absorption rendered visible by the glass 

 tube, the lower end of which represented the open 

 mouths of the absorbing vessels, f In observing 

 that the sanguiferous and lymphatic vessels have a 

 similar communication between their extremities and 

 the thorax, he has apparently left out of considera- 



* " L'uffinitc dcs parois vasculaircs pour les iiiatiercs absorbecs 

 et.-Hit supposec la cause, ou, si 1'ou vent, I'mie dcs causes, <le 1'ab- 

 sorption," &c. Journal <!<' Phyriologie, t. i. p. 8. 



j- " Kx|M-riniciit:il Researches on the Influence of Atmospheric 

 I'n SMIIV upon the lilooil in the Veins, upon Absorption," &c. By 

 David Barry, M.D. &e. London, 1826. 



