82 OTTO GLASER. 



pear to remove equal quantities of copper from a w/ 1,460 solution. 

 £n fact, in certain instances, the solutions after exposure to the 

 eggs seemed to contain more copper than I had added. With 

 dechorionized material the results were almost bizarre. Such eggs 

 usually appeared to absorb less than the normal, though at times 

 the opposite was true. Their most frequent irregularity was the 

 apparent addition of copper to the sea-water. Where was the 

 error? 



I sharpened my technique as much as possible. After each 

 experiment a few drops of sulphuric acid were added to the solu- 

 tion to be tested in order that any copper carbonates formed dur- 

 ing the experiments might be converted. I also used ammonia to 

 intensify the colors. Nevertheless the harvest of inconsistencies 

 continued. 



It was then that I recalled Lillie's " copper-avid substance in the 

 cortex of the egg-" This might explain everything, yet only if it 

 could be shown that the untreated normal Arbacia egg actually 

 contains copper. 



VI. Demonstration of Copper in Arbacia Eggs. 

 A. Preliminary Considerations. 



Was there any likelihood of demonstrating copper in the normal 

 egg"? In the literature I found the following especially pertinent 

 facts : 



100 gr. fresh Asterias rubens contain 2.45 mg. Cu. 



.100 gr. fresh Stichopus regalis contain 2.83 mg. Cu. 



100 Sepia eggs contain 0.5-0.8 mg. Cu. 



100 gr. dry hen's yolk contain 2.00 mg. Cu. 



The first three items are from Aron's ('09) discussion in Oppen- 

 heimer's Handbuch ; the last from an investigation by Fleurent and 

 Levi ('io 1 ). 



Measurable quantities of copper, then, have been reported for 

 certain echinoderms and at least two kinds of eggs. 



B. Qualitative Tests for Copper. 

 It is hardly necessary to discuss the very large number of pre- 

 liminary tests made at Woods Hole during the summer of 1921. 



