2 TUE TONER LECTURES. 



opportunity permitted him to make upon tlie human body at 

 interrupted intervals. 



M. Petit tUouglit as follows : — 



After ligation or compression of an artery a clot is generally 

 formed above the place or on the cardiac side of the ligation, 

 or tlie point of compression. 



The constitution and density of the coagulum are varied 

 in different portions by reason of the massing together in places 

 of the several elements composing it — the position of the cor- 

 puscles and the fibrin being determined by their specific gravity 

 relative to that of the liquor sanguinis. 



It is more advantageous that the clot should be formed 

 of the white part (lymph) only, than that it should consist of 

 a mixture of the lymph and the red globules. 



The clot in a short time becomes as firmly united to the 

 sides of the artery as the granulation-tissue w^iich forms cica- 

 trices is to the lips of wounds. This intimate union once 

 formed, not only is secondarj- hemorrhage prevented, but the 

 clot in this state remains and disappears only as cicatrices 

 diminish, in proportion to their condensation, 



M. Morand (Sur les changements qui arrivent aux arteres 

 couples ; ou I'on fait voir qu'ils contribuent essentiellement a 

 la cessation de I'llemorrhagie. Memoires de rAcade'mio Koyale 

 des Sciences, tome liii. Annee 1736) communicated some ob- 

 servations and conclusions upon the subject matter of the fore- 

 going essays of M. Petit, le Chirurgien. 



Tlie paper concludes with the following sentence, wliich is in 

 reality a formulation of his opinion concerning nature's mode 

 of stopping blood, viz. : — 



"The changes whicli take place in the arteries (retraction 

 and contraction of the walls) contribute, then, to the cessation 

 of hemorrhage conjointly with the clot, generally in every case ; 

 and if it is possible that the artery alone or the clot alone can 



