2 A. J. GOLDFARB. 



vitelline space. With increasing age, or in freshly liberated eggs 

 in poor physiologic condition, the rate of membrane formation 

 was correspondingly retarded, and the perivitelline space was 

 correspondingly diminished. In late stages of physiologic 

 deterioration, the membrane-forming substance was entirely 

 gone, and no membranes were formed. Synchronous with these 

 changes in the fertilization membrane, other changes took place, 

 of which the most important for my present purpose were, first 

 a progressive loss of surrounding jelly layer of the eggs, and sec- 

 ondly a change in permeability of the cortical layer of the eggs 

 which permitted an increasing volume of sea water to penetrate 

 into the egg, increasing its volume and rendering the cytoplasm 

 increasingly viscous. 



When the eggs reached this stage of aging or physiologic de- 

 terioration, agglutination took place. Such aged or stale eggs 

 had actually reached the condition that experimenters (Loeb, 

 Driesch, Goldfarb and de Haan) have sought to produce ex- 

 perimentally. 



Loeb used hypotonic sea water, which swelled the eggs and 

 burst their membranes. Later he used hyperalkaline dilute sea 

 water, which in addition made the cortical layer viscous. Driesch, 

 Goldfarb, and de Haan removed the surrounding jelly and the 

 fertilization membranes by mechanical treatment and then 

 centrifuged the eggs in sea water or in hyperalkaline sea water. 

 Goldfarb later used only such eggs as had been kept in the labora- 

 tory for about five hours, and without other treatment obtained 

 much larger numbers of agglutinations. These investigators as 

 well as Morgan, Nussbaum, Wilson, Zur Strassen and others had 

 observed from time to time the spontaneous agglutination 

 (and fusion) of eggs in different species of urchins, as well as in 

 other animals. It is very probable indeed that in these instances 

 spontaneous agglutinations occurred in the eggs that had suffi- 

 ciently aged, and hence were in the condition most favorable 

 for their ready agglutination. Certain it is that in all of my cul- 

 tures of aging eggs, and in all three species, agglutination took 

 place in every experiment in which the eggs were allowed to age 

 over a sufficiently long period. The facts concerning the aggluti- 

 nation in aging eggs may be summarized as follows : 



