Experimental Study of Growth 241 
hatching (when the records begin in the table) there is a steady 
and rapid growth due to the inbibition 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: — 
Hours or BRoopInG ABSOLUTE WEIGHT IN GRAMS Per CENT OF WATER 
48 0.06 83 
54 0.20 go 
58 0.33 88 
gr 1.20 83 
96 1.30 68 
124 2.03 69 
264 6.72 59 
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: — 
AGE IN WEEKS ABSOLUTE WEIGHT IN GRAMS PER CENT OF WATER 
6 0.975 97-5 
17 36.5 91.8 
22 100. 92.0 
24 242. 89.9 
26 569. 86.4 
30 924. 83.7 
35 928. 82.9 
39 1640. 94.2 
R 
