410 THE LAWS OF OBGANIC 



preaching to congestion, or, at the same time, 

 that the surface of the body is deprived of its 

 necessary blood, but simply to communicate to 

 the mind an idea of a mode of circulation pecu- 

 liar to this stage of life. 



CCCCXCL Exertion, of whatever kind, has 

 a tendency to augment the flow of blood ; and, 

 whenever its motion is facilitated, a greater quan- 

 tity, in a given time, is transmitted to the lungs 

 with augmented impetus; and these, from their 

 organization and office, are calculated to experi- 

 ence the first pressure made upon the system at 

 the different periods of life. 



CCCCXCII. If we take into consideration that 

 the lungs, in some individuals, are predisposed 

 to hemorrhagy, or that the circulation of blood, 

 or that the activity of the internal organs is na- 

 turally different or variable, it is not difficult to 

 explain the occurrence or absence of hemoptysis. 

 CCCCXCIII. Hemorrhoids, hemorrhagia ani, 

 and diseases of the same kind, which are called 

 passive, from the veins being the seat or source 

 of these, are accounted for by Dr CULLEN in 

 the following manner: 



" The proportional density of the coats of the 

 veins to that of the coats of the arteries, is greater 

 in young than in old animals. From which it 

 may be presumed, that the resistance to the pas- 

 sage of the blood from the arteries into the veins 

 is greater in young animals than in old ; and, 



