284 GENERAL ANATOMY. 



irritation to produce the contraction of the arteries. Zi miner- 

 mann, Parry, Verschuir, and Hastings have remarked that mi- 

 neral and vegetable acids cause the same effect. Thomson and 

 Hastings have seen the same thing occur by the action of am- 

 monia. Verschuir, Hunter, and Hastings have observed the 

 simple action of the air and of temperature to produce this con- 

 traction. Hastings has also obtained the same result by the 

 application of oil of turpentine, the tincture of cantharides, the 

 solution of muriate of ammonia, and of sulphate of copper. 

 Bikker and Van den Bosch have caused the contraction of the 

 arteries by electricity; Guilo and Rossi by galvanism; Home 

 Jias observed it even on the application of an alkali on the 

 nerve adjoining an artery. Vital contractility, little apprecia- 

 ble in the larger arteries, augments successively in the smaller 

 .ones. 



We may also cite as a farther proof of the existence of the 

 irritability .of the arteries, the augmentation of their contrac- 

 tion in inflammation and in neurosis. Thus, in panaris, in 

 angina tonsillaris, in tic douloureux, &c.; we see and feel the 

 arteries beat on one side much more than on the other. We 

 sometimes observe differences of the same kind in hemiplcgia. 

 The same thing also occurs in pregnancy, and in many other 

 hygid or morbid phenomena, accompanied with a local de- 

 velopment of vessels. 



We may therefore conclude, from what proceeds, that during 

 life the arteries possess both elasticity and irritability; that 

 elasticity predominates in the large, and irritability in the small 

 arteries; that arterial irritability is more or less dependent upon 

 the nervous influence. In the course of time, the vasa vaso- 

 ntm diminishing, the nerves of the arteries gradually disap- 

 pearing, and the middle membrane becoming harder, the arte- 

 rial irritability lessens more and more, and even the elasticity 

 itself is greatly impaired. 



422. The sensibility of the arteries is null or extremely 

 obscure. Verschuir relates one single experiment in which 

 an animal seemed to feel pain on the application of a mineral 

 acid. According to Bichat, on injecting an irritating liquid 

 a lively pain appears also to be produced. 



