130 THE FUNCTION 



sorption occurred, no poisonous effects ensued ; nor did 

 they, even for some time afterwards ; and when they became 

 apparent, they instantly subsided on the re-application of the 

 glasses. The pressure of the rim of the glass, he says, was not 

 the cause of the non-appearance of poisoning, because if the 

 deleterious substance was passed under the skin beyond the 

 boundary of the glass, no ill effect occurred as long as the glass 

 remained over the wound : an incision between the site of the 

 poison and the rim destroyed the efficacy of the glass. b Yet 

 others have found the same result from the cupping-glass pressed 

 down and not exhausted, and even from the pressure of a solid 

 body. c 



Dr. Barry's experiments, however, would not prove that at- 

 mospheric pressure is the cause of absorption : they would merely 

 show its co-operation, and that the propulsive powers of the 

 absorbents are insufficient when opposed by the removal of it. 

 Pecquet, nearly two centuries ago, considered whether the chyle 

 was absorbed by suction ; and concluded against the opinion, by 

 observing, that, if a ligature was placed upon the thoracic duct 

 or the lacteals of the mesentery, and all effect of vacuum thus 

 prevented, the lacteals swelled on the intestinal side ; therefore, 

 said he, " non trahitur chylus sugiturve." d 



The pressure of ordinary respiration and of muscular efforts 

 is also seen to drive the chyle forwards in the lacteals. 



" But their principal action, by which they take up fluids more 

 or less rapidly, eagerly absorbing some and absolutely rejecting 

 others 6 ," like the lacteals, " depends upon the peculiar modifica- 



b Experimental Researches, p. 102. The application of a vacuum in poisonous 

 wounds has been recommended from the days of Hippocrates to those of Dr. 

 Parry (Cases ef Tetanus and Canine Hydrophobia), but its effects never shown so 

 beautifully as by Dr. Barry. He recommends that the cupping-glasses should be 

 first applied for an hour ; that, the suppression of absorption for some hours being 

 thus ensured, the part should be excised, and then the glasses re-applied to remove 

 any portion of the poison that may remain, for the vacuum was found to extract 

 some of the poison. 



c See the translation, by Drs. Hodgkin and Fisher, of Dr. Edwards's work, 

 hereafter quoted, p. 401. sq. 



d Dissertatio Anatomica de drculatione sanguinis et chyli motu, p. 76. Paris, 

 1651. 



e " On this remarkable difference consult T. Fr/Lucr. Albrecht, Commeniatio 

 (honoured with the Royal Prize) in qua proponitur recensus eorum alimentor. et 

 rtiedicaminum, quibus, sive tubo alimentario sint ingesta, sive communibus corporis 

 integumentis applicata, ingressus in sy sterna vasor. sanguifer. aut concessus a natura, 

 nut negatus sit. Gotting. 1806, 4to." 



