MEMOIR OF JOHN BARCLAY. 35 



and close observation, which Sir George Ballingall 

 considers the most practically useful of all his writings. 



The generality of anatomical writers since Haller, 

 who had treated of the arteries, having usually sub- 

 stituted the description of some common variety for 

 the description of the general character, he wished 

 to supply the deficiency, or rather to rectify the mis- 

 take; and from various preparations, and the de- 

 scriptions of different authors, proposed to ascertain 

 the general range allowed to each of the larger 

 arteries, as to their origin, their ramification, and 

 extent of distribution. 



In order to render his descriptions more precise, 

 although he proposed to take but few liberties with 

 the names of the arteries, yet on purpose to accommo- 

 date his language to the immortal discovery of Harvey, 

 he used the names proposed in his own nomenclature. 



As there are two principal trunks of the arteries, 

 I. The Pulmonary, so named from being ramified 

 through the pulmones or lungs, commencing at the 

 right ventricle, and carrying blood of a dark colour, 

 which, on being exposed to the action of the air 

 in its passage through the lungs, assumes a florid 

 red colour ; and II. The Aorta, which transmits the 

 red blood through the medium of its branches to the 

 system at large ; he proposed for the one to sub- 

 stitute the term pulmonic, and for the other systemic 

 artery; and consequently the blood which flowed 

 through each to be similarly designated : pulmonic 

 and systemic blood. The appearances of the arteries 

 vhich he described as general facts or as common to 



