Vol. XXXV. July, 1918. No. i. 



BIOLOGICAL BULLETIN 



EFFECTS OF AGING UPON GERM CELLS AND 

 UPON EARLY DEVELOPMENT. 



PART III. CHANGES IN VERY AGED EGGS 



A. J. GOLDFARB, 

 COLLEGE OF THE CITY OF NEW YORK. 



In the previous two studies it was shown that, beginning with 

 maturation, definite progressive morphologic and physiologic 

 changes took place in the egg, both within and without the body, 

 such as (i) an increase in volume of the egg, (2) a loss of sur- 

 rounding jelly layer, (3) a retardation in the rate and change in 

 the manner of forming the fertilization membrane, (4) a retarda- 

 tion and inhibition in cleavage. These changes served as measur- 

 able and corroborative evidences of the physiologic condition 

 or vitality of the eggs of a female at any time, and served to 

 measure the deterioration or loss of vitality with age. 



There were other symptoms or evidences of physiologic de- 

 terioration, especially in late stages of ageing, or overripening, 

 which will be discussed briefly in this paper. These changes 

 include: (i) Agglutination of eggs, (2) fusion of eggs, (3) abnormal 

 cleavage, (4) separation of blastomeres and (5) cytolysis of the 



eggs. 



The same technique, the same nomenclature, the same pre- 

 cautions and the same three species of sea urchin were used as in 

 Parts I. and II. For details of these I must refer to these studies. 



AGGLUTINATION OF EGGS. 



In Part II. it was shown that freshly removed eggs in good 

 physiologic condition formed fertilization membranes within two 

 minutes, at a rate accelerated with age, and with a wide peri- 



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