220 ANIMAL PHYSIOLOGY. [LESSON 65. 



without teeth, for the dividing and mastication of their food, 

 the stomach is wonderfully modified to suit an extraordinary 

 want. All the other requisites of a well-developed nutrimental func- 

 tion they are possessed of. 



970. The most elaborate and perfect form of these organs is met 

 with in the class MAMMALIA. Notwithstanding the various modifi- 

 cations and complications of the nutrimental canal to meet special 

 wants, the general principle remains always the same, and the sever- 

 al accessory organs essential to perfect digestion of the several kinds 

 of food, upon which the members of the class are destined to sub- 

 sist, are there. 



LESSON LXY. 



NUTRITION IN MAN, CONCLUDED. 



971. What a wonderful piece of mechanism is the human intes- 

 tinal tract, with its millions of villi all periodically actively engaged, 

 its mucus-crypts, its countless glands, its capillary, and its nervous 

 systems ! That it should at any time get out of repair is by no 

 means surprising ; the wonder is that it remains in a healthy condi- 

 tion, especially from the difficult and impossible labors many of us 

 call upon it to perform. The true rules for a sound and healthy 

 stomach are few and simple to eat when we are hungry, and to 

 drink only when nature requires it. 



972. How many persons there are who occupy themselves inces- 

 santly in eating, and as incessantly in drinking water ! Has it ever 

 occurred to them that the highly complicated machinery necessary to 

 digest food requires repose ? 



973. The muscular coat of the stomach having labored to digest 

 a meal, demands rest, and must have it, if its vigor be cared for. 

 On the other hand, if it be attempted to make the necessary organs 

 always work, they flatly refuse, and will not do any thing ; whereby 

 the worst form of dyspepsia results. A pint of water weighs one 

 pound, and the stomach must attempt the same means to get rid of it 

 as though it were the same weight of solid food, but with less suc- 

 cess ; all its contractions are in vain the water eludes these efforts 

 till the fatigued muscles yield in despair.. 



974. But there are other forms in which we do ourselves a great 

 wrong, namely, by eating improper, because indigestible food, or by 

 eating food improperly prepared. ThuS young meats (Veal and 



