SCIENTIFIC PROCEEDINGS. 
Abstracts of the Communications. 
LIBRARY 
YORK 
BOTANICAL 
Fortieth meeting. 
College of Physicians and Surgeons, Columbia University. October 
jp, IQIO. 
How could increase in permeability to electrolytes allow the 
[From the Histological Laboratory of Cornell Medical College and 
the Laboratories of the Carnegie Institution at Tortugas, Fla., 
and the U. S. Bureau of Fisheries at Woods Hole, Mass.] 
I found that the electric conductivity of the sea urchin's egg 
increased about one fourth on fertilization or when made to 
develop parthenogenetically with sea water containing acetic acid. 
Galeotti 1 observed changes in electric conductivity of animal 
tissues and explained them by the formation and dissociation of 
ion-proteid compounds. However he observed that the freezing 
point sometimes did not change appreciably and never changed 
in proportion to changes in conductivity. Therefore it seems 
more probable that the changes in conductivity were due to 
changes in permeability of membranes. 
It seems probable, from observations on the volume of the egg, 
that its osmotic pressure does not appreciably change, even 
momentarily, on fertilization. For this and other reasons 2 I 
conclude that the increased electric conductivity is due to in- 
creased permeability of the plasma membrane. 
!Zeit. f. Biol., neue folge, xxv, 289, xxvii, 65. 
2 Dynamics of Cell Division, ii, Am. Jour. Physiol., in press. 
I (526) 
development of the egg ? 
By J. F. MOOLENDON. 
