RALPH S. LILLIE 787 



of exposure to the solutions was 6 minutes. Examination in India 

 ink suspension about 15 minutes later showed complete removal of 

 the jelly in the eggs of lot A, of which about 25 to 30 per cent had 

 also formed fertilization membranes. In the eggs of lot B the jelly 

 was unaltered and no fertilization membranes were formed. Part 

 of the eggs of both lots were fertilized with sperm at 4.13 p.m.; the 

 next day about 70 per cent of the eggs of lot A had formed blastulae, 

 largely abnormal, while almost all of lot B had developed normally. 



Other experiments of the same kind give similar results. Exposure 

 to pure NaCl solution for some minutes removes the jelly; it also 

 causes agglutination and injures the eggs, as shown by a certain 

 degree of impairment and abnormality in development, and forms 

 fertilization membranes in a considerable proportion of eggs. All 

 of these effects are prevented by the addition of a little CaCl2 to the 

 solution. 



The antagonistic action of calcium is shown in much more dilute 

 solution than the above; e.g., in m/400 CaClo (199 volumes of 0.54 

 M NaCl plus 1 volume of m/2 CaCl2), with the same treatment as 

 above, the jelly remained intact. Further experiments to determine 

 the limit of the effective concentrations were not tried. Magnesium 

 chloride has a similar action in preventing the solution of the jelly, 

 but is less effective. 



The question of whether calcium can be replaced in this relation 

 by other polyvalent metals has not yet been experimentally tested 

 except in the case of aluminium. Eggs were placed in pure 0.54 m 

 NaCl (lot A), and in 99 volumes of 0.54 m NaCl plus 1 volume of 

 m/2 AICI3 (lot B) ; the solutions were changed twice by centrifuging 

 and decanting as before. On return to sea water after 6 minutes 

 in the solutions the eggs of lot A were found free from jelly and largely 

 agglutinated, while those of lot B retained the jelly, although this 

 was somewhat thinner than in the untreated control eggs; there was 

 no agglutination. The probability is that many other polyvalent 

 cations would be found to have this effect, as in other cases of 

 antagonism. 



