418 THE LAWS OF OKGANIC 



dilation, yet at the same time are subject to 

 every alteration of the sanguiferous system, the 

 absence, and not the occurrence of hemoptysis, 

 becomes a matter of surprise. 



DVII. It was formerly believed that hemop- 

 tysis was the consequence of a rupture of some 

 of the pulmonary vessels ; but modern patholo- 

 gists have clearly shewn that this circumstance 

 seldom happens except when a vessel, traversing 

 a tuberculous excavation, is partly destroyed by 

 the progress of disease. Hemoptysis is some- 

 times the consequence of an aneurism opening 

 itself into the trachea, bronchia, or substance of 

 the lungs. 



DVIII. When the quantity of blood which is 

 poured from the lungs is even considerable, it is 

 regarded by L^NNEC as a sanguineous exhala- 

 tion into the pulmonary parenchyma, and is de- 

 scribed by this pathologist under the name of 

 Pulmonary Apoplexy.* 



DIX. Cold, and the sudden removal of at- 

 mospheric pressure, are enumerated by CULLEN 

 among the exciting causes of hemorrhagy. It 

 is almost impossible for the former to produce an 

 active form of the affection, as this does not depend, 

 as is supposed by some, upon a state of conges- 

 tion determined by the slow and gradual influ- 

 ence of cold, but is more justly to be referred to 

 an increased action of the capillary vessels. In 



* JLjENNEC del Oscultation Mediate, Vol. II. p. 45. Edit. 

 Prima. 



