24 A. J. GOLDFARB. 



D. I. With increasing physiologic deterioration, there oc- 

 curred another type of irregularity, namely, more or less complete 

 separation of the blastomeres. 



2. Such separation occurred in every experiment that was 

 carried over a sufficiently long period, and with further aging 

 separation of blastomeres was increasingly complete. 



3. The separation of the blastomeres occurred with suc- 

 cessive cleavages. 



4. In Toxopneustes and Hipponoe, separation usually occurred 

 eight to ten hours after physiologically good eggs were removed 

 from the female. In Arbacia about 24 hours were required. 

 The variation in onset in different females was due to variation 

 in the physiologic condition of the eggs at liberation. 



E. I. With still further physiologic deterioration (or "age- 

 ing") cytolysis set in. There were two types of cytolysis, namely 

 cytolysis by liquefication or enlargement, and by fragmentation 

 or reduction. 



2. The onset of cytolysis differs in the eggs of different females 

 depending upon the physiologic condition of the eggs at the time 

 of liberation. 



3. Cytolysis occurred three or more times as rapidly in Toxop- 

 neustes and Hipponoe than in Arbacia. This difference is in 

 part due to accelerated metabolic rate at the higher temperature 

 of the southern species, partly due to increased HO ion con- 

 centration of sea water at Tortugas and partly to protoplasmic 

 differences of the different species of eggs. 



F. Agglutination, fusion, abnormal cleavage, separation of 

 blastomeres and cytolysis of the eggs are phenomena correlated 

 with intense physiologic deterioration of the eggs, and were 

 observed in all cultures in which the eggs were sufficiently dete- 

 riorated. 



Seven independent groups of tests were used to determine the 

 degree of deterioration. These tests corroborate one another. 

 Any one test, with suitable precautions, measures the vitality of 

 the eggs. From any one, the other manifestations of aging may 

 be predicted. A group of tests offers the most convincing means 

 of measuring exactly the degree of senescence of any sample of 

 of eggs. 



