OP THE ARTERIES. 289 



either on a surface, the result of an amputation, or in the con- 

 tinuation of the soft parts, the blood issues in a full stream and 

 by a constant jet, alternately rising and lowering until the 

 circulation is greatly enfeebled; then the bleeding diminishes 

 and stops, either to recommence one or more times when the 

 weakness has ceased, and to continue even to death, or ceases 

 altogether. In this latter case, very rare in the human species, 

 the artery being retracted in its sheath and in the surround- 

 ing cellular tissue, the blood infiltrates and coagulates around 

 the end of the vessel; it coagulates also in the end itself to a 

 greater or smaller distance, always determined, however, by 

 the situation of the nearest branch, through which the circu- 

 lation still continues to take place. The extremity of the arte- 

 ry is then obstructed and plugged, nearly in the same manner 

 as is the mouth of a bottle by the cork, and by the wax with 

 which it is covered. The artery being no longer influenced by 

 the alternate distention it previously experienced, gradually 

 shrinks; its divided extremity undergoes traumatic inflamma- 

 tion, and becomes the seat of a plastic exudation; the blood, 

 cogulated internally and externally, is gradually absorbed, the 

 artery cotinues to contract, it is converted into a mere cord, 

 and commonly disappears, or is changed into cellular tissue as 

 far as the neighbourhood of the nearest branch, which con- 

 tinues to carry on the circulation. 



429. When an artery is distended lengthwise, it greatly 

 elongates at first by sliding in its sheath, favoured by the cellu- 

 lar tissue which surround it; after yielding a great deal with- 

 out breaking, it begins to tear internally. The external mem- 

 brane is the last part torn, after being elongated and thinned 

 nearly in the manner of a tube of glass melted and drawn over 

 a lamp. After being torn, the extremities of the artery re- 

 treat less than they have yielded, and the blood jets out, at 

 first, as in the preceding case; but ordinarily, it soon stops, 

 never to reappear. This quick and entire cessation of the 

 hemorrhage, which almost always occurs in similar cases, has 

 been ascribed to the retraction of the artery and to other ima- 

 ginary causes. I am convinced, by many experiments per- 

 formed on animals, and by many observations made on man, 



