Experimental Study of Growth 



241 



hatching (when the records begin in the table) there is a steady 

 and rapid growth due to the inhibition of water. The dry sub- 

 stance even decreases during this time. Then follows a period 

 when the dry substance increases enormously, so that the percent- 

 age of water falls, but nevertheless a great amount of water 

 continues to be absorbed, and is mainly responsible for the in- 

 crease in size. 



The next table gives results obtained by Potts for the growth 

 of the chick : 



Here we see that the percentage of water falls in later stages, and 

 the increase in weight must be due in a greater degree to the 

 assimilation of the materials of the yolk. Nevertheless, there 

 must be a continuous absorption of water from the albumen or 

 white, for, although the percentage sinks, the amount of water 

 is continually greater. 



Similar results have been found by Fehling for the human 

 embryo as shown in the following table : 



