253 ANNALS NEW YORK ACADEMY OF SCIENCES 



an initial gift, Professor jST. L. Britton has generously promised $5,000. 

 The Academy then adjourned. 



Heney E. Ceampton, 

 Acting Recording Secretary. 



SECTION OF ASTEONOMY, PHYSICS AND CHEMISTEY 



7 PEBiiUAEy, 1916 



Section met at 8 :20, Vice-President Ernest E. Smith presiding. 

 The following program was presented : 



A. J. Goldfarb, Chemical and Physical Changes of Eggs and 

 Theie Significance in Geafting. 



Arthur E. Hill, Eepoet on the Absoebing Powee op Ceetain 

 Colloids. 



SUMMAEY OF PaPEES 



Professor Goldfarb stated that when eggs of sea-urchins {Toxopneustes 

 variegatus) are removed from the ovaries and placed in sea water at 

 room temperature (84° F.) a series of changes take place that affect the 

 character of the fertilization membrane, the rate of fertilization membrane 

 formation, the viscosity of the egg protoplasm, and the rate of cleavage. 

 These changes are approximately in proportion to the time factor, reach- 

 ing a maximum just before death. These changes permit of ready fusion 

 of separately fertilized eggs, whose further development into fused larvae 

 was elsewhere described. 



Professor Hill stated that absorption occurs when chromium, iron or 

 aluminum are precipitated by ammonium chloride and ammonium 

 hydroxide in the presence of salts of cobalt, nickel, manganese or zinc. 

 Using 100 mg. of the absorbing metal, it was found that as much as 

 40 mg. of nickel Avould be so completely absorbed as to be undetectable 

 in the filtrate. The order of absorbents, from greater to less, is as 

 follows : chromium, aluminum, iron ; and the metals absorbed are in the 

 order nickel, zinc, manganese and cobalt. It Avas found that the absorp- 

 tion is roughly proportional to the alkalinity. Moderate excess of am- 

 monia will increase absorption so greatly that chromium hydroxide will 

 carry down more than its own weight of nickel or zinc salts. In keeping 

 with this generalization, it was found that separation of the two groups 

 of metals by use of solid barium carbonate reduces the absorption greatly 

 and the separation by sodium acetate in slightly acid solution reduces 

 tlie absorption to an almost undetectable amount. A precise study of 



