Human Physiology. 



maturity ; the front teeth, made for biting fruits, vegetables, and 

 other comparatively soft substances; the side teeth for mashing 

 and grinding seeds, nuts, and all matters which require to be 

 reduced to pulp, and mingled with the saliva. The teeth of 

 every animal point out its natural diet. The beaver lives on 

 the bark and tender twigs of plants, and we have seen his 

 teeth for cutting and grinding them (Fig. 10, Part Second). 



Here, in this skull of a 

 carnivorous, or flesh-eating 

 animal (Fig. 38), we have 

 strong tusks for holding and 

 tearing its prey, and at the 

 sides of the jaws sharp cut- 

 ting teeth for dividing flesh 



in pieces, which is then swal- 

 38. SKULL OF CARNIVGKA. 



lowed without further mas- 

 tication. The teeth of men are similar to those of the fruit- 

 eating mammalia; and there can be no doubt that fruits, nuts, 

 and grains, or the seeds of vegetables, are the most natural and 

 therefore the most healthful food of the human species. This 

 is the testimony of all the most distinguished anatomists and 

 physiologists. 



Beneath the under jaw, and near the ear, on each side of the 

 face, are glands which separate from the blood the first fluid 

 which aids the process of digestion the saliva. The moment 

 food touches the tongue even when its odour penetrates the 

 nostrils, and often at the sight, or even the thought of pleasant 

 food, these glands are excited to unusual activity; the nerves 

 increase the flow of blood to them, quite independent of any 

 action of the heart; the nervous power, by some unknown 

 chemistry, transforms a portion of the blood into a bland, 

 slightly alkaline fluid, which is, or should be, thoroughly 

 mingled with the food, and begins to dissolve it. The office 

 of the tongue is to taste the food, and by this taste excite the 



