SOME CHEMICAL CHANGES IN THE DEVELOPING FISII EGG. 
155 
VI . — Digestive experiments. 
Character of eggs. 
Substance 
(grams). 
Residue. 
Grams. 
Percent- 
age. 
24 hours after fertilization 
11 clays after fertilization 
20 days after fertilization 
2. 0442 
1.698 
1. 7767 
0. 0428 
. 0570 
. 1297* 
2. 08 
3. 35 
7.24 
* Phosphorus determination in the residue of eggs 20 days after fertilization, 0.137 grams 
of the residue : MgP 2 O 3 =0.014 gr., P = 2.65 per cent. 
VII . — Determination of the nucleo-bases. 
Character of eggs. 
Substance. 
Grams. 
Per cent. 
1. 8611 
0. 0022 
0. 12 
2. 0227 
. 0438 
2. 16 
1.519 
.0325 
2. 14 
1.2132 
.0455 
3. 75 
It would be premature to draw any very broad conclusions from tbe little work done 
for tbe present. Sucb conclusions should be deferred until the data have increased 
considerably. Tbe results of this work, however, tend to indicate that iu tbe developing 
fish egg tbe processes of synthesis are preceded by those of decomposition. (Consult 
Table V.) In the first stage after fertilization the proteids diminish in quantity ; basic 
nitrogenous substances are formed at their expense. Later the basic substances 
decrease in quantity and proteids grow. Whether the molecules of those proteids are 
formed from the basic substances will be investigated in the future. It is also seen 
that the character of the proteids is changed daring the development of the egg, tbe 
combined proteids as we may term them, such as nucleoproteids, increasing greatly 
in quantity. The importance of mineral salts for the formation of tissues can be illus- 
trated by the increasing quantity of mineral substances in the egg in the course of 
its growth. 
