EXPERIMENTATION AND PHYSIOLOGY 



in persons having pathologic conditions in 

 these glands. Another little gland lying at the 

 base of the brain, the pituitary body, about the 

 size of a pea, is found to have vital functions 

 of a similar character. The testicles and 

 ovaries produce materials which have an im- 

 portant physiologic relation to the functions 

 of the brain. The new knowledge that has 

 been gained by the experimental study of all 

 of these glands in different parts of the body 

 shows that the brain is much under the influ- 

 ence of the other organs of the body. Now, 

 when these glands become diseased or injured, 

 surgery is directed to conserving as much of 

 their structure as possible, and they are no 

 longer removed in toto as was once the practice. 



One of the important chapters in biology is Regenera- 

 that which deals with regeneration. It has tion. 

 thrown light of incalculable value upon animal 

 economy. Biologists found that when a hydra 

 has been divided into two parts each part forms 

 a new animal. Indeed, if the animal is divided 

 in a certain way each part will develop a com- 

 plete new individual, and to continue propaga- 

 tion along this line all one needs is a sharp 

 knife. Spiders and crabs possess the power of 

 growing new feelers and claws in the place of 



