THE MARVEL OF GROWTH 115 



These two creatures, the chick and the rabbit, are good 

 illustrations of the difference between some oviparous and 

 many viviparous animals. But, for both alike, surroundings 

 make all the difference in the world in their after life. If 

 they have too little food or unfit food, if their environment 

 is too hot or too cold, too wet or too dry, they will not grow 

 as they should. 



For example, Dr. Minot reports the effect of temperature 

 on the development of tadpoles. Four were taken from the 

 same set of eggs, and each was kept in water of a different 

 temperature. The illustration shows the result. The one 

 marked D was kept so warm and comfortable that the mul- 

 tiplying cells did their best. After three days he was a lusty 

 young fellow of goodly size and shape. A was kept so cold 

 that he barely lived. The result is evident. His cells were so 

 chilled that they could not multiply normally. 



These and other experiments prove that, from the begin- 

 ning, the condition of the environment vitally affects the 

 development of the individual. When this environment is 

 right, the development is rapid and normal ; when it is wrong, 

 the development is sure to be abnormal. 



Dr. Minot tells us that in the first year of its life a normal 

 seven-pound baby gains 200 per cent, and will weigh 2 1 pounds 

 by the end of the year. In the second year he will gain 20 per 

 cent, and after that about 10 per cent each year until he is 

 fourteen years old. Dr. Minot also pictures the growing baby 

 and shows that never afterwards does any human being learn 

 so much or grow so fast as during its first eventful year 

 after birth. Two things it can do from the start : it can take 

 nourishment, and it can thrash its arms and legs about aim- 

 lessly. Comparatively soon, also, it gains the powers of touch, 

 hearing, sight, taste, and smell. Through these five roads 



