Human Physiology. 201 



tion leaves the body at the lower extremity of the alimentary 

 canal. Some indigestible matters, as the outer husk of grains, 

 the skins of fruits, and some seeds pass through the body, and 

 a certain amount of such matter appears to stimulate the action 

 of the bowels and prevent constipation. Bread made of fine 

 flour, pastry, and too large a proportion of concentrated food, 

 as flesh, fish, eggs, etc., cause constipation. Bread of unbolted 

 wheat, fruits which contain much woody fibre, figs with their 

 numerous small seeds, coarse oatmeal, spinach, and other greens 

 and vegetables, on the contrary, keep up a healthy action of the 

 intestines. 



It is evident that so extensive and complex an organism as 

 that devoted to the digestion and absorption of the alimentary 

 matters constantly required by the system may be liable to 

 great derangements and disorders, and we have in the stomach 

 and intestines the origin and centre of many diseases. If the 

 digestive system is in good order, the health and vigour of the 

 whole body are secured. If the action of the stomach and in- 

 testinal canal, and the glandular system connected with them 

 is impaired, good blood cannot be formed, nervous power can- 

 not be generated; without nervous power there cannot be 

 healthy secretions or good digestion : thus we have a circle of 

 evils, each intensifying the other. A man in ordinary health 

 digests boiled rice in one hour that is to say, it passes out of 

 the stomach, dissolved into chyme. It may be two or three 

 hours before it is absorbed from the intestines, and passes 

 through the glands, and becomes blood. Wheat bread takes 

 a little longer; cooked flesh requires from two to four hours; 

 potatoes, cabbage, and other vegetables, from an hour and 

 a-half to three hours; hard white of egg, four to six hours. 

 But much depends upon thorough mastication and insalivation. 

 More depends upon the energy of the nervous system. If that 

 has been exhausted by excessive labour, or pleasure, or anxiety ? 

 digestion is slow, and may be entirely suspended. If, after a 



