DEVELOPMENT OF THE BODY AFTER BIRTH 331 



by many changes in the body. In the male the formation 

 of spermatozoa and beard take place, the larynx develops 

 more powerfully, and the voice changes. Sexual desires 

 awaken. The manly character appears. In castrated 

 children these phenomena are not observed. Female 

 puberty, which occurs a little earlier than in the male, is 

 accompanied by ovulation and menstruation, and the external 

 sexual organs are covered with hair and the mammary 

 glands develop. 



4. OLD AGE, DEGENERATION, AND PHYSIOLOGICAL 



DEATH 



The prime of life in man extends from the twenty-fifth to 

 the forty-fifth year. After this degeneration sets in, the 

 body weight and length decrease. Metabolism and the 

 functions of the organs are reduced. In high old age a great 

 debility of the organs, especially of the brain and heart, sets 

 in, which finally results in physiological death or death by 

 senile decay. In the female this degeneration begins with 

 the climacteric, the cessation of ovulation and menstruation. 

 The greatest old age in man may be over one hundred 

 years. According to the mortuary statistics, the average 

 length of human life in civilized countries is thirty years. 



