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REVUE DES QUESTIONS SCIENTIFIQUES. 
d’éprouver une lésion grave par suite de la turgescence et 
de la distension des veines. Mais les deux organes sont 
défendus contre ces dangers au moyen d’un bel arrangement 
des muscles du cou, qui recouvrent et protègent les troncs 
veineux.... Il faut aussi remarquer que le tissu plat formé 
de fibres musculaires et qui couvre l’œil, — c’est-à-dire le 
muscle orbiculaire, au moyen duquel nous clignons et fer- 
mons les yeux, — fait partie du même arrangement. Il agit 
en comprimant le globe oculaire dès que la poitrine est 
violemment contractée, comme dans la toux, etc.; de la 
sorte, il ferme les] veines situées derrière l’orbite, et prévient 
l’engorgement des fines branches qui se ramifient dans les 
couches délicates Jde l’œil (i). » 
(1) “ The blood which returns to the heart by the veins, flows towards the 
■» ckest in a slow and easily interrupted stream ; the force which propelled it 
» when issuing from the heart by the arteries being exhausted before it 
» enters the veins. From this weakness of the current, it follows that the 
». blood collected in the great veins close to the entrance of the chest, — as 
>» the jugular veins, for example, — may be stopped by a slight cause ; 
« wlience congestion of the minute branches will be the conséquence, and 
»> serious injury may be occasioned to the more délicate organs from which 
« the blood returns. Now there are certains conditions of the chest in brea- 
-» thing, during which the veinous blood is thus interrupted. As we draw in 
« the breath, the blood flows along the veins with perfect facility, because 
». the superior opening of the chest is then enlarged, and the succion, which 
». draws air into the windpipe, has also the effect of increasing the force of 
»» the current of the returning blood. But when we expel the air, and thereby 
»» diminish the area of the chest, an obstruction" takes place in the flow of 
»» blood in the veins, and if the act of expiration be strong, régurgitation 
»» may be produced. This interruption, and rétrogradé motion of the blood in 
». the large veins of the neck, gorges the smaller vessels ; the effect of which 
„ may be seen in a person seized with a fit of coughing or of sneezing : for 
»» his face then becomes suffused with red, and the superficial veins turgid 
»» with blood. It is therefore obvious that if the veins of the surface of the 
». head become congested, in such violent conditions of breathing, the deeper 
»> veins, returning the blood from the brain and the eye, will also be over- 
»> distended from the same cause. Consequently, the délicate textures of these 
» important organs will be in danger of suffering serious injury from the 
»» loadsd and turgid condition of the veins. But both organs are defended 
