140 Organisms from Eggs 



Boveri has done by showing that the egg grows from 

 the wall of the ovary and that that part of the egg 

 which is connected with the wall of the ovary gives 

 rise to the ectoderm layer, while the opposite part gives 

 rise to the mesenchyme and the intestine. This shows 

 a connection between the orientation of the egg in the 

 wall of the ovary and its stratification. While this 

 does not solve the problem of stratification in the egg 

 it gives the clue to its solution. 



The ultimate origin of stratification probably goes 

 back to the fact of the presence of watery and water- 

 immiscible substances, such as fats. The experiments 

 by Beutner and the writer have shown that the electro- 

 motive forces which are observed in living tissues 

 originate at the boundaries between a watery and a water- 

 immiscible phase, like oleic acid or lecithin. 1 In his 

 earlier writings 2 the writer had thought that the colloids 

 had special significance and this idea seems to prevail 

 today; but the actual observations have shown that 

 the phase boundary fat-water is of greater importance. 

 Needless to say the fats if not present in the cell 

 from the beginning can be formed in the metabolism. 



4. All the "regulation" in the egg is of a purely 

 physicochemical character; it consists essentially of a 

 flow of material. If this idea is correct, the apparent 



1 Loeb, J. f and Beutner, R., Biochem. Ztschr., 1912, xli. f i; xliv., 303; 

 1913, li., 288; li., 300; 1914, lix., 195. 



2 Loeb, J., The Dynamics of Living Matter. New York, 1906. Intro- 

 ductory Remarks. 



