426 



J. GRAY 



Whilst in the acid sokition no change, either visible or physio- 

 logical, takes place, apart from the fact that the acid rapidly 

 penetrates into the egg and can be detected by means of 

 indicators (Gray, 8). It may be noted that in such a solution 

 the activity of normally fertilized eggs is completely stopped. 



It is only when the unfertilized eggs are removed from the 

 butyric-acid solution to sea-water containing a definite con- 

 centration of hydroxyl ions, that fertilization membranes 

 appear ; and that the physiological properties of the fertilized 

 eggs are acquired and are carried on at a speed equal to that 

 produced by normal fertilization. It is now that the eggs 

 become more permeable to water (R. S. Lillie, 22) and to ions 

 (McClendon, 25 ; Gray, 18), and that there is a marked increase 

 in oxygen consumption. If the vitelline membrane be regarded 

 as a continuous lipoid film, then an interesting parallel experi- 

 ment can be carried out by the emulsification of olive oil. 



Olive oil + no fatty acid forms no emulsion with distilled 



w^ater. 

 Olive oil + no fatty acid forms no emulsion with alkaline 



water. 

 Olive oil + fatty acid forms no emulsion with distilled water. 

 Olive oil + fatty acid forms a complete emulsion with alkaline 



water. 



The process of artificial membrane formation and that of oil 

 emulsification are dependent on the same factors : (a) the 

 existence of a fatty acid in the oil, (b) the existence of 

 a minimum concentration of hydroxyl ions in the neighbouring 

 aqueous phase. In each case the resultant product shows 

 a marked increase in permeability to water and to ions. 



