340 



He proceeded to shew, that, as the artery is elastic, the impulse 



of the heart cannot reach every branch at the same moment, 



that undulations, or partial distention, must characterize the pro- 

 gress of the heart's impulse along the artery. 



He argued against the opinion that there is no other quality 

 than that of tonicity in the circular fibres of the artery. For 

 tonicity, according to the definition of physiologists, being a per- 

 manency of action, which admits of no relaxation, it would fol- 

 low that the artery had two properties exactly the same; for 

 tonicity and elasticity would present exactly the same kind of re- 

 sistance to the blood impelled by the heart. 



But, — granting to these fibres the vital property of muscularity, 

 — since the healthy action of a muscular fibre is characterized by 

 relaxation as much as by contraction, we perceive that the higher 

 muscularity of the extreme vessels implies that they are more easy 

 of dilatation, as well as more powerfiil in contraction ; and that 

 the dilatation and contraction of successive portions of the artery 

 must, like an increasing wave, bestow a higher degree of activity in 

 the vessels remote from the heart. Sir Charles deferred the read- 

 ing of the Second Part of his pajier. 



The following Donations were presented : — 



The Transactions of the Linnean Society of London. Vol. xvii. 



Parts 2, 3, 4 ; and Vol. xviii. Part 1. 

 The Proceedings of the Linnean Society of London. Nos. 8 and 



9. — By the Society. 

 Transactions of the Society for the Encouragement of Arts, Manu 



factures and Commerce. Vol. liii. Part 1. — By the Society. 

 Journal of the Asiatic Society of Bengal. Nos. 99, 101, and 102. 



— By the Society. 

 Travels in the Himalayan Provinces of Hindustan and the Pun- 

 jab. By William Moorcroft and George Trebeck. Edited 



by H. H. Wilson, Esq. 2 vols. 8vo. — By the Asiatic Society 



of Bengal. 

 Comptes Rendus Hebdomadaires des Seances de rAcademie des 



Sciences. Tome x. Nos. 19 to 26 ; Tome xi. and Tome xii. 



Nos. 1 to 5 — By the Academy. 

 Memoires de T Academic Royale des Sciences de ITnstitut de 



France. Tomes xiv. xv. xvi. and xvii. 

 Memoires presentes pars divers Savants a T Academic Royale de 



rinstitut de France. Tome 5 — By the Academy. 

 Voyage dans la Russie Meridionale et la Crimee. Par M. de De- 



