CIRCULATION OF THE BLOOD. 357 



We therefore must come to the conclusion that the ac- 

 tions performed by the spinal cord, when the brain is 

 removed, or its power destroyed, do not depend on sensa- 

 tion ; but upon a peculiar property of that organ by which 

 impressions made upon certain parts, necessarily excite 

 motions of an automatic character. See Carpenter's 

 Physiology^ p. 3548. 



CIRCULATION OF THE BLOOD. 



We have already given an account of the circulation 

 in insects, the amphibia, fishes, and in man (pages 

 127-53,) and we propose here to continue the subject, by 

 giving a more detailed account of the arterial system of 

 the human body, with an engraved illustration. 



If the student will compare the figure here introduced, 

 with Fig. 96 where the heart, lungs, and diaphragm are 

 represented, he will see the heart, aorta, and a number 

 of the other large blood vessels figured on a larger scale 

 than in the present figure. 



The word artery, cornes from the Greek, and signifies 

 " to hold air," from the circumstance that the large ves- 

 sels near the heart, are found empty after death, and 

 hence were supposed to contain air only. 



Having given an account of the circulation in man, 

 with figures of the larger vessels at p. 132, we proceed to 

 enlarge upon the same subject by means of Fig. 9, which 

 represents the arterial system, a, The temporal artery. 

 6, The carotid artery, c, The vertebral artery, d, The 

 subclavian artery, e, The axillary artery, f, The aorta. 

 g, The brachial artery. , The coeliac artery, f, The 

 renal artery, j, The iliac artery, k, The radial artery. 

 /, The femoral artery. 7??, The tibial artery, n, The pos- 

 terior tibial artery, o, The peroneal artery, p, Artery 

 of the foot. 



Observations on the Arteries. The arterial system of 

 the greater circulation entirely springs from one large 

 trunk, the aorta, which originates in the left ventricle of 

 the heart, and is the only vessel which passes out of that 

 cavity. Tt first ascends nearly to a line with the shoul- 



