THE MOTION OF THE BLOOD. 185 



cernible in the plant called dionaea muscipula, nor in the sensitive 

 plant, nor in those zoophytes which appear gelatinous masses; 

 yet contractility dependent on life is very manifest in them. 



Verschuir actually found the larger arteries contract on irritating 

 them with a scalpel, in fifteen out of twenty experiments. 2 Dr. L. 

 Bikker, and J. J. Vandembos assert the same of the aorta, and 

 Van Geuns of the carotid when influenced by electricity.* Zim- 

 merman, Bichat, and Magendie, saw the arteries contract upon 

 the application of acids, but the two last considered it a chemical 

 change. Dr. Hastings, however, saw the same from the application 

 of ammonia. When a ligature was placed on the aorta of a frog by 

 Dr. M. Hall, the circulation was almost instantly arrested, first 

 in the capillaries, then in the veins, and the blood, during ten or 

 fifteen minutes, would move on in the arteries for some seconds, 

 and then all at once rapidly retrograde, and so alternately. 1 * 

 J. Hunter found the posterior tibial artery of a dog contract so as 

 nearly to prevent any blood from passing through it on merely 

 being laid bare, and facts similar to this are mentioned by Drs. 

 Hastings, Fowler c , Jones d , and the Drs. Parry. Dr. Stevens de- 

 stroyed a rabbit's brain with a bodkin, and opened the chest. The 

 lungs collapsed, and the heart lay motionless. On opening the 

 pericardium, a branch of the coronary arteries on the right ven- 

 tricle began to contract, and acted forcibly till it had driven all 

 its blood into the ventricle. It now was still, and the right auricle 

 began to contract, and continued acting for two hours and three 

 quarters, the ventricle being almost motionless. 6 Dr. Marshall 

 Hall says, that the superficial muscles and heart of batrachian 

 reptiles become rigidly contracted by water of 120 ; and that, if an 

 artery and vein be also plunged in it, the artery grows rigid like 

 muscles, and cylindrical, while the vein suffers no apparent 

 change. f The fact of continued contraction, and of alternate 

 contraction and relaxation in arteries, being occasioned by stimuli, 

 is therefore certain ; and, although some have not succeeded 

 in stimulating them, we must remember that others have 



z De Art. et Yen. vi Irrit. 



z See Hastings, 1. c. The introduction to this work is a body of information 

 on the present subject. 



b A Critical and Experimental Essay on the Circulation, &c. by Marshall Hall, 

 M.D. London, 1831. p. 78. 



c Disputatio inauguralis de Inflammatione. d On Hemorrhage. 



e 1. c. p, 57. f 1. c. p. 78. 



