FERTILIZATION AND OXIDATION ol 
were replaced in normal sea-water. Sperm was added to the 
unfertilized eggs after their transference to ordinary sea-water. 
The unfertilized eggs, which had been in the sea-water contain- 
ing potassium cyanide for two days, developed in quite a normal 
manner, whereas the eggs which had been fertilized before they 
were put into the cyanide sea-water were no longer able to 
develop beyond the blastula stage after an exposure of only 
twenty-four hours to this solution. An exposure of five hours’ 
duration to the cyanide sea-water was already harmful to the 
fertilized eggs; this was shown by the fact that while such 
eggs did develop after transference to ordinary sea-water, 
many larvae died during the first two days.! 
These experiments leave no doubt that fertilization gives rise 
to a class of chemical reactions in the egg which can proceed 
independently of oxidations. It is very likely that other 
reactions besides oxidations, e.g., hydrolyses, take place in the 
egg. If such hydrolyses lead to the formation of harmful 
oxidizable substances, e.g., lactic acid, it can be understood 
why lack of oxygen must in time lead to the death of the 
fertilized egg; without oxygen the harmful substances, which 
are quickly rendered harmless by oxidation (or converted into 
substances like CO., which can be eliminated), can now accumu- 
late in the cell. Assuming that such hydrolyses are set up in 
the egg by fertilization, while they are lacking or are very slow 
in the unfertilized egg, we could understand why the fertilized 
egg suffers more quickly than the unfertilized egg from lack of 
oxygen or from the prevention of oxidations by potassium 
cyanide. 
5. Wasteneys and the writer raised the question whether the 
oxidations are the independent variable in the development of 
the egg.2 From all we know, we should expect that hydrolyses 
i Loeb, ‘‘Versuche ueber den chemischen Charakter des Befruchtungsvor- 
gangs,’ Biochem. Zeitschr., I, 189, 1906. 
2Loeb and Wasteneys, ‘‘Sind die Oxydationsvorgiinge die unabhingige 
Variable in den Lebenserscheinungen ?”’ Biochem. Zeitschr., XXXVI, 345-56, 1911. 
