16 Artificial Parthenogenesis and Fertilization 



treatment with the hypertonic solution or with the temporary- 

 suppression of oxidations. 



Ten years ago the writer found that the life of the untreated 

 unfertiHzed egg can be prolonged for some time (though not 

 indefinitely) by suppressing the oxidations in the egg. This 

 indicated that the oxidations in the unfertilized egg are one of 

 the causes which lead to the premature death of the unfertilized 

 egg. This conclusion is supported by the fact that the mature 

 unfertilized egg of the starfish dies much more quickly than the 

 unfertilized egg of the sea-urchin; the rate of oxidations in the 

 mature but unfertilized egg of the starfish is comparatively much 

 greater than in the mature but unfertilized egg of the sea-urchin. 



We must therefore conclude that the oxidations going on in 

 the mature but unfertiHzed egg are one of the causes that lead 

 directly or indirectly to its death; and that in the light of this 

 fact it appears as if the process of fertilization rendered the egg 

 immune against oxidations, or, in other words, transformed 

 the egg from an anaerobe into an aerobe. 



10. Since physiologists who are not famihar with the litera- 

 ture often state that artificial parthenogenesis does not lead to 

 the production of larvae capable of development, it might be 

 well to point out that such statements are contrary to fact. 

 Delage has raised two parthenogenetic larvae of the sea-urchin 

 during sixteen months to the stage of sexual maturity.' Both 

 were males. Loeb and Bancroft raised a parthenogenetic frog 

 through metamorphosis and found that its sex glands con- 

 tained eggs.^ If the raising of larvae were not such a tedious 

 process, parthenogenetic animals would exist today in large 

 numbers, since parthenogenetic larvae may be normal and 

 apparently healthy. 



■ Delage, Compt. rend. Acad. d. Sc, OXLVIII, 453, 1909. 

 ' Loeb and Bancroft, Jour. Exper. Zool.. XIV, 275, 1913. 



