94 



OTTO GLASER. 



as hematoxylin, indicates also the presence of diffuse copper in the cytoplasm. 

 This is shown by the finer stipples. 



The cortical layer is shown as differentiated into two zones : an inner, free 

 from copper ; an outer, immediately under the egg membrane with consider- 

 able concentration of copper. The evidence is again the triple-nitrite test on 

 normal eggs, and the xanthate and ferrocyanide tests on eggs which had 

 been exposed to solutions of copper in sea-water. 



The vitelline membrane is shown as a line whose irregularly spaced black 

 beads represent regions in which the triple nitrite was concentrated. The 

 membranes of eggs exposed to copper solutions appear as continuous heavy 

 black lines without beads. 



The region outside the vitelline membrane represents the chorion with its 

 diffuse and highly rarefied copper. 



The diagram is intended to indicate distribution. It cannot indicate quan- 

 titative differences accurately because a variety of tests was used and the extent 

 of discoloration depends not primarily on the quantities of copper but on 

 the molecular size of the copper compounds formed. These are necessarily 

 different in the several tests. 



XI. Order of Magnitude of the Quantities of Copper 



Involved. 



Quantitative data on the copper content can not be given. The 

 methods for determining the copper are, indeed, reliable enough; 

 but, unfortunately, the chorion alone prevents anyone from know- 

 ing how many eggs are present in i c.c, and until this number is 

 definitely ascertained our initial measurements can hardly articu- 

 late closely with the results of chemical methods unusual in deli- 

 cacy. For the present, then, we can arrive only at approximations. 



I. The Ovarian Egg. 



Eleven c.c. of ovary were dissolved in n c.c. of concentrated 

 nitric acid and after complete destruction diluted to ioo c.c. with 

 distilled water. Ten c.c. of this solution were evaporated to dry- 

 ness and the incinerated ash dissolved. After neutralization with 

 ammonia the volume was restored to 9 c.c. To this was added 

 1 c.c. of a solution of potassium ethyl xanthate whose concentra- 

 tion was 1 gr. per 1,000 c.c. of distilled water. This same amount 

 was added to 9 c.c. of a copper sulphate solution containing 10 /x 

 gr. of copper per c.c. 



Colorimetric comparisons were then made, and the concentra- 

 tion, C 2 , of the unknown calculated from the concentration, C lf of 

 the standard and the depth of the unknown, D 2 , necessary to match 



