282 OTTO GLASER. 



the two filters were then gently mixed with a blunt glass rod, thus 

 insuring a uniform distribution, in the one case of eggs and sperm ; 

 in the other of eggs and sea-water. 



Although the experiment gave the expected result, it was not 

 possible in this way to measure the loss of material from the eggs 

 undergoing fertilization. For this, the filter papers and the 

 capillary spaces between the papers and the funnels held back too 

 much liquid. Nevertheless it was very evident that the amount 

 of fluid secreted under these conditions by the inseminated eggs 

 was markedly greater than that produced in the same time by the 

 controls. 



Evidently something leaves the eggs as they are undergoing 

 fertilization a fact which relates very easily to the observed 

 decreases in diameter. In their turn these harmonize well with 

 the observed cortical changes themselves the basis of postulated 

 and reasonably w T ell attested increases in permeability. Indeed, 

 we have here a system of closely interdependent events and for 

 that reason I consider the loss in volume a matter of sufficient 

 theoretical interest to warrant the expenditure of great care in 

 those cases in which its demonstration is possible. 



This opportunity the Arbacia egg seems to offer. The decrease 

 in its diameter is not an illusion but the index of a loss in volume 

 correlated with a real loss in mass; it also is not an oddity. 

 Other eggs exhibit the same phenomenon. Furthermore the fact 

 itself is not unintelligible. Indeed it may be related significantly 

 and without violence to the entire constellation of events which 

 together make up the initiation of development. 



AMHERST COLLEGE, 



November 25, 1923. 



LITERATURE. 

 Chambers, R. 



'21 Microdissection Studies, III. Some Problems in the Maturation and 



Fertilization of the Echinoderm Egg. BIOL. BULL., Vol. XLL, pp. 



318-350. 

 Carrey, W. E. 



'19 The Nature of the Fertilization Membrane of Asterias and Arbacia Eggs. 



BIOL. BULL., Vol. XXXVII. , pp. 287-293. 

 Glaser, O. 



'13 On Inducing Development in the Sea-Urchin (Arbacia punctulata], together 



with Considerations on the Initiatory Effect of Fertilization. Science^ 



Vol. XXXVIII. , pp. 446-450. 



