208 ANIMAL PHYSIOLOGY. [LESSON 60. 



fluid. Is it not much more probable that they are, in function, parotid 

 glands ? 



900. To show the difficulties that surround this question, it may 

 be well to remark, that in the Calf, when cooked, all these glands 

 taste precisely like the (so-called) sweetbread, and have the same 

 general appearance. 



901. The organ called by butchers the " throat-sweetbread," is, 

 in reality, the submaxillary gland ; and the " heart-sweetbread " is 

 the Thymus gland, which is always of great size in young animals. 



902. The true sweetbread, or pancreas, is never eaten. 



LESSON LX. 



THE PEOPEETIES OF THE GASTBIC JUICE AND MUCUS. 



903. If we eat a dry cracker, we cannot swallow it until it be 

 moistened with the saliva ; and the same thing takes place with 

 Cows and Sheep, when they are fed upon dry hay. 



904. When food that has been properly insalivated, reaches the 

 stomach, it is destined to come in contact with two other elements, 

 both of which, so far as experiments on artifical digestion have ex- 

 tended, are imperatively necessary for its final resolution into chyme. 

 These are, the weak acid, known as gastric juice, and mucus / and 

 without the combination of the two, in their full integrity, there can 

 be no healthy digestion. 



905. From the chemical composition of one of these agents (the 

 gastric juice), it must be evident that those persons who habitually 

 drink much water, must necessarily impair the function of the stom- 

 ach, as they thereby dilute an already weak acid, until it be power- 

 less ; in fact there can be no doubt that the practice of water- drink- 

 ing to excess is as much a vice as the too frequent indulgence in 

 strong potations, and leads to precisely the same consequences 

 death. * 



906. Moreover, water taken in large quantities with a full meal, has 

 another very bad effect : when there is food in the stomach to digest, 

 the capillaries, previously nearly empty, are turgid with blood, which 

 has been withdrawn from the surface of the body and the limbs, to 

 meet an immediate, special want cold water thrown upon this ex- 



