330 THE POPULAR SCIENCE MONTHLY. 



the duty usually fulfilled by an artery.' He suggested that this weak 

 power, by which the portal vein propelled its blood, was compensated 

 for by a suction force communicated to the current of the blood by 

 the actions of respiration. These reasonings have been confirmed by 

 certain experiments of M. Bernard." " In persons, then, who lead a sed- 

 entary life, this auxiliary force for promoting the circulation of blood 

 through the liver is diminished, blood stagnates in the gland, and the 

 functions of the organ are deranged, these results being all the more 

 likely to arise if the liver be at the same time over-stimulated by 

 errors in diet." * 



Take another organ. The stomach is a muscular organ, being fur- 

 nished with bands of muscular fiber, which squeeze and press the food, 

 turning it over and over, so that it may be the better permeated by 

 the juices which digest it. It, too, is stimulated by exercise, especial- 

 ly by an exercise like walking or riding, which increases its move- 

 ment. This motion makes easier work for the organ and increases 

 its activity. It increases its activity also in another way, by demand- 

 ing more of it. For increased work by any part of the body means 

 increased destruction of tissue. "To repair the waste is the office of 

 the blood, as the distributor of the material to be supplied. The main 

 furnisher of this new material in the right form to do its work is the 

 stomach. For food is both the fuel which keeps our bodily machinery 

 going and the material by which the machinery itself is repaired. 

 The stomach, with the duodenum, is the place where all this material 

 is prepared to do its work in the most economical way. More exer- 

 cise, then, means more waste, more waste means more repair, and more 

 repair means a greater demand for food and water. The more, then, 

 we waste any part of the body by exercise (within certain limits), if 

 there is due repair, the better off is that part. The strength of the 

 body, as a whole, and of each part of the body individually, is thus 

 ever in relation to its newness." f 



The bowels, too, the great sewers of the bodily system, inclosed in 

 pliable walls needing constant motion and fresh supplies of blood for 

 their healthy exercise, feel the action of the breathing lungs, and are 

 sensible of every turn, twist, rising, and falling of the body. Deprive 

 the body of exercise, and you deprive the bowels of blood and proper 

 action, and bring in a long train of evils, a catalogue of which can be 

 read in the advertising columns of almost any daily newspaper. 



The kidneys, too, are affected by physical exercise. Doubtless 

 they receive a certain stimulation from the motion communicated to 

 them in exercise, but as they are engaged in the work of eliminating 

 from the system its excess of liquid with certain effete matter in solu- 

 tion, and as the skin is also concerned in a similar work, they are 

 affected by exercise mostly with reference to this joint action. The 

 more active the skin is, the less work the kidneys have to do. 



* "Functional Derangements of the Liver," Hurchison. f McLaren. 



