AND ANIMAL LIFE, 113 



in the uterine functions, all of which have the ten- 

 dency to increase the natural internal circulation 

 or determination of blood, giving rise to disorgani- 

 zations of the lungs, weakness of digestion, de- 

 ranged secretions of the abdominal viscera, pal- 

 pitation of the heart, and disturbance of the 

 mental powers. It is not necessary to insist 

 further on the correctness of this opinion, by 

 adducing other illustrations : the minute and 

 efficient investigation will be found, not in any 

 single chapter or view, but in examining the 

 general principles which are proposed, in the 

 variety of aspects which different diseases, seasons, 

 and circumstances present. 



CXIII.If we consider the nature of the diseases 

 which occur after the prime of life, which arise 

 simply from the extension of the same principles 

 that we have traced from youth to maturity, we 

 shall be agreeably surprised to find, that Dr CUL- 

 LEN referred the greater number of these diseases 

 to a venous plethora, depending, as he supposed, 

 on a difference in the proportional density of the 

 coats of the arteries and veins. He imagined 

 that in early life the coats of the veins have a 

 proportional density greater than those of the ar- 

 teries, on which account the plethoric state of the 

 latter is to be regarded as the cause of many con- 

 stitutional derangements and diseases ; but at a 

 subsequent period the density of the coats of the 

 arteries becomes superior to that of the veins, and 



H 



