680 ABSORPTION. 



might be no point of contact between it and the surrounding parts. He 

 then let fall upon its surface and opposite the middle of the card a 

 thick watery solution of nux vomica, a substance, that exerts a power- 

 ful action on dogs. He took care, that no particle of the poison touched 

 any thing but the vein and cord ; and that the course of the blood, 

 within the vessel, was free. Before the expiration of three minutes, 

 the effects he expected appeared, at first feebly, but afterwards with 

 so much activity, that to prevent fatal results he had to inflate the 

 lungs. The experiment was repeated on an older animal with the same 

 results ; except that, as might have been expected, they were longer in 

 exhibiting themselves, owing to the greater thickness of the parietes of 

 the veins. 



Satisfied, as regarded the veins, he now directed his attention to the 

 arteries: the results were the same. They were, however, slower in 

 appearing than in the case of the veins, owing to the tissue of the arte- 

 ries being less spongy. It required upwards of a quarter of an hour 

 for imbibition to be accomplished. In one of the rabbits, which died 

 under the experiment, they had an opportunity of discovering, that 

 absorption could not have been effected by any small veins, that had 

 escaped dissection. One of the carotids, the subject-vessel of the 

 experiment, was taken from the body; and the small quantity of blood, 

 adherent to its inner surface, was found by M. Magendie, and his friends 

 who assisted at the experiment, to possess the extreme bitterness that 

 characterizes nux vomica. These experiments were sufficient to prove 

 the fact of imbibition by the large vessels, both in the dead and in the 

 living state. His attention was now directed to the smaller; which 

 seemed, a priori, favourable to the action, from their delicacy of organi- 

 zation. He took the heart of a dog, that had died the day before, and 

 injected water, of the temperature of 86 of Fah., into one of the 

 coronary arteries, which readily returned by the coronary vein into the 

 right auricle, whence it was allowed to flow into a vessel. Half an 

 ounce of water, slightly acidulated, was now placed in the pericardium. 

 At first, the injected fluid did not exhibit any signs of acidity; but, in 

 five or six minutes, the evidences were unequivocal. 



From these facts, M. Magendie 1 draws the too exclusive deduction, that 

 "all bloodvessels, arterial and venous, dead or living, large or small, 

 possess a physical property capable of accounting for the principal 

 phenomena of absorption." We shall endeavour to show, that it 

 explains only certain varieties of absorption, those in which the 

 vessel receives the fluid unmodified, but that it is unable to account 

 for other absorption in which an action of selection and elaboration is 

 necessary. 



After these experiments were performed, others were instituted by 

 MM. Sgalas 2 and FodeVa, 3 from which the latter physiologist attempts 

 to show, that exhalation is simply a transudation of substances from the 

 interior of vessels to the exterior ; and absorption an imbibition or pas- 

 sage of fluids from the exterior to the interior. The facts adduced by 



1 Precis, &c., ii. 283. 2 Magendie's Journal de Physio)., ii. 217. 



3 Recherches Experiment, sur 1' Absorption, &c., Paris, 1824, and Magendie's Journal, &c., 

 iii. 35. 



