436 



SCIENCE 



[N. S. Vol. XXVI. No. 666 



they had not been treated with the hyper- 

 tonic solution; if the same eggs are put 

 after the treatment with hypertonic sea- 

 water free from oxygen for from 30 to 50 

 minutes into hypertonic sea-water contain- 

 ing oxygen they will develop normally 

 when put back into normal sea- water. The 

 dominant role of the oxygen in the action 

 of hypertonic sea-water upon the unfer- 

 tilized egg is still more manifest in experi- 

 ments on eggs which possess no membranes. 

 If we put the unfertilized eggs of 

 Strongylocentrotus directly into hyper- 

 tonic and hyperalkaline sea-water, e. g., 

 50 c.c. sea-water plus 10 c.c. 2^NaCl plus 

 1 c.c. N/10 NaHO and leave them in such 

 a solution at 15° C. for about two hours, 

 many eggs will develop after they are 

 transferred back to normal sea-water, while 

 others will be injured and perish in a short 

 time. Both effects, however, are only pro- 

 duced if the hypertonic solution contains 

 oxygen. If it is carefully freed from oxy- 

 gen or if the oxidations are inhibited by 

 KCN the eggs are intact when taken out 

 of the solution. They will neither develop 

 nor disintegrate when put back into normal 

 sea-water. If after a few hours sperm is 

 added to such eggs they will develop.- 

 However one may vary the experiment, the 

 result is always the same, namely that a 

 hypertonic solution stimulates or modifies 

 the development of the egg only in the 

 presence of free oxygen. This seems to 

 indicate that the effect of the hypertonic 

 solution in artificial parthenogenesis con- 

 sists in k modification of the phenomena of 

 oxidation in the egg; the latter are led 

 back into the right channel. This is the 

 reason why the eggs do not disintegrate 

 but develop if they are treated with hyper- 

 ionic sea-water after the artificial mem- 

 brane formation. 



VI 



If we summarize all the experiments on 



artificial parthenogenesis it seems that the 

 essential feature of the process of fertiliza- 

 tion consists first in a liquefaction or 

 hydrolysis or both, of fatty compounds, 

 and second, in the starting of processes of 

 oxidation in the right direction. In some 

 forms, e. g., Asterina, the latter will take 

 place naturally if only the former process 

 is started. In the eggs of many forms the 

 process of liquefaction or saponification of 

 lipoids occurs under the phenomenon of 

 membrane formation. These processes of 

 the liquefaction of fats and hydrolysis and 

 oxidation form apparently the basis of the 

 synthesis of nucleins. It is possible, but 

 far from proved, that among the fatty 

 compounds involved in the process of 

 hydrolysis are the lecithins. 



These results are in harmony with the 

 facts observed in the germination of oily 

 seeds. The process of germination is an 

 analogue to the starting of the development 

 in the animal egg, inasmuch as resting cells 

 are thrown into the process of cell divi- 

 sion and this process is based upon the 

 synthesis of nucleins. Experiments on the 

 germination of the castor bean have shown, 

 according to Hoyer, that as soon as the 

 seeds are put into water a hydrolytie 

 process is started which results in the 

 formation of acid, chiefly cai-bonic, lactic, 

 and to a smaller degree, acetic acid. 

 Through these acids a lipolytic enzyme is 

 activated by which the oil of the seed is 

 rapidly hydrolyzed. The rest of the 

 process of germination is primarily a 

 nuelein synthesis. This synthesis depends, 

 as in the case of the egg, upon the presence 

 of free oxygen, since Moritz Traube has 

 shown that seeds can not germinate except 

 in the presence of free oxygen. I think 

 the chemistry of the germination of seeds 

 is essentially the chemistry of nuelein syn- 

 thesis, and I believe the method of starting 

 this synthesis is essentially the same as in 

 the fertilization of the egg. 



