A ]S D PHYSIOLOGY. 



1S3 



part of the body in great numbers, and are almost constantly 

 at work in removing the waste particles, it follows that in 

 process of time a large part, or even the whole of the body, 

 will be removed. And it is generally admitted that the 

 whole body is actually renewed every few years, although 

 the precise number can not be stated, since so many circum- 

 stances modify the change, such as exercise, the amount of 

 food taken, and climate, as well as other causes not so easily 

 understood. It is, however, quite probable that the period 

 of ten years is sufficient to complete the change in most in- 

 dividuals, and the number is stated by some as low as seven. 



HYGIENIC INFERENCES. 



333. 1. From the structure and functions of the Digestive 

 Organs we can derive some hints as to the manner of pre- 

 venting acute and chronic diseases in them. 



334. Danger of Eating too much.— 2. We see that there 

 is a great danger of eating too much. Large quantities of 

 food distend the coats of the stomach, and give too much labor 

 for them to perform. As a natural consequence the gastric 

 glands are weakened from excessive action, and then indiges- 

 tion or some other diseased action is sure to follow. And in 

 how much better health would multitudes in the higher classes 

 of society be kept, if some of the numerous dishes they use 

 were omitted! And in this country the remark applies to 

 nearly all classes. 



335. We are apt to eat too many Kinds of Food.— 8. We 

 also see that our meals are generally made up of too many 

 kinds of food. In the habits of the lower animals we dis- 

 cover a great simplicity of diet. Even in those whose ana- 

 tomical structure closely resembles that of man, the appetites 



332. How great changes are effected in the body by the Lymphatics? In what length 

 of time is the body probably entirely renewed? 334. What is the injury from eating 

 too much ? 335. What is said about eating too many kinds of food ? 



