116 



Pub. Puget Sound Biol. Sta. Vol. 2, No. 40 



N/20000), to the blastula and gastrula stages in a pH of 7.25 (N/TSOO), 

 and to the evaginated gastrula stage in a pH of 6.7 — 7.05 (N/3000 — 

 N/5400). 



From table 2 it may be seen that fertilization and cleavage will take 

 place after 6 hours of treatment with H2SO3 (pH of 7.2 — 8.0), altho 

 abnormalities appear after a period of ll/o hours of treatment. It may 

 be that sulphur dioxide has the power of decreasing oxidation and there- 

 fore of prolonging the life of the unfertilized egg. Loeb (1917) found 

 that potassium cyanide has this effect. 



Table 3. Effects of H^SO^ on fertilized eggs 



In the second type of experiment the eggs were fertilized in sea- 

 water, then placed in HjSOg at different stages of development (from 

 25 minutes after fertilization to the blastula stage) and left to finish 

 their growth under these conditions (table 3). Using acid with a pH 



