94 



AGE, GROWTH, AND DEATH 



ing weight is a variable function of the age, but it is 

 sufficiently exact for our present needs, and has the 

 advantages of simplicity and rapidity in its practical 

 application. 



In the next slide (Fig. 28) which we are to see 

 upon the screen we have fny method of measuring the 

 rate of growth illustrated graphically. There is here 

 a curve which represents the rate of growth of male 

 guinea-pigs. The figures at the bottom indicate the 

 age of the animals in days. When guinea-pigs are 

 born they are very far advanced in development, and 

 the act of birth seems to be a physiological shock 



\ 



1 5811 n 1] MM 45 60 75 90 105 120 135 ISO 165 ISO 195 ZioriayJ 241 



FIG. 28. CURVE SHOWING THE DAILY PERCENTAGE INCREMENTS IN WEIGHT 

 OF MALE GUINEA-PIGS. 



from which the organism suffers, and there is a lessen- 

 ing of the power of growth immediately after birth. 

 But in two or three days the young are fully re- 



