DAVENPORT: THE ROLE OF WATER IN GROWTH. 
77 
Amblystoma, toads, and frogs. All series showed the same thing; 
the most complete series is that given in the following table : — 
Embryos of Frogs. 1895. 
Date. 
Days after 
hatching. 
Avg. wt. 
mg. 
Wt. of dry 
substance, 
mg. 
Wt. of water. 
mg. 
% of water. 
May 2. 
1 
1.83 
.80 
1.03 
56 
“ 3. 
2 
2.00 
.83 
1.17 
59 
“ 6 . 
5 
3.43 
.80 
2.63 
77 
“ 8. 
7 
5.05 
.54 
4.51 
89 
“ 10. 
9 
10.40 
.72 
9.68 
93 
“ 15. 
14 
23.52 
1.16 
22.36 
96 
June 10. 
41 
101.0 
9.9 
91.1 
90 
July 23. 
84 
1989.9 
247.9 
1742.0 
88 
These results are graphically represented in Fig. 3. The curve 
and table show that, exactly as in plants, there is a period of slow 
Fig. 3. Graphic representation of last column of Table, showing percentage of water 
in frog embryos from 1 to 84 days after hatching. Compare with Fig. 2. 
growth accompanied by abundant cell division — the earliest stages 
of the egg. Then follows, after the first few hours, a period of 
rapid growth due almost exclusively to imbibed water, during which 
the percentage of water rises from 56 to 96; lastly comes the 
period of histological differentiation and deposition of formed 
substance, during which the amount of dry substance increases 
