THE BIOLOGY OF THE CELL SURFACE 



tive-factor theory not only is not supported b}^ fact but is 

 contradicted by it. 



We may dismiss the superficial cytolysis-corrective 

 factor theory of parthenogenesis for the following reasons: 

 All eggs including those of sea-urchins need treatment only 

 with a single means. Further, for sea-urchins' eggs, the 

 cytolytic eflFect that the theory stresses, results from over- 

 exposure to the acid. Finally, the fact that the order of 

 treatment in the double method can be reversed, makes the 

 theory even for the single egg of the sea-urchin untenable. 



These obvious failures of the theory however did not pre- 

 vent the exaggeration of its significance to an unusual 

 degree. The discovery that eggs could be induced to 

 develop without the spermatozoon gave rise to extravagant 

 claims by experimental embryologists themselves and 

 aroused fantastic notions among laymen. Many hailed it 

 as a demonstration of the creation of life. As if the unfer- 

 tilized egg were not alive ! According to one report, to 

 create life is easy since the means for inaugurating the life- 

 process are at once simple and close at hand: one needs only 

 two chemicals, vinegar and salt, found in every kitchen, to 

 start the egg on its long and complicated journey of develop- 

 ment, the end of which is the adult form. The occurrence 

 of natural parthenogenesis in the meantime was given scant 

 attention; indeed, in some quarters it was entirely over- 

 looked. The one fact alone, that nature dispenses with 

 spermatozoa for the development of certain eggs — those 

 of rotifers, aphids, bees and others — this recognized 

 fact of natural parthenogenesis that we have known for 

 years, should have saved us from making excessive claims 

 concerning the significance of experimentally induced 

 parthenogensis. 



As soon as the superficial cytolysis-corrective factor 

 theory for experimental parthenogenesis had been elab- 

 orated, the attempt was made to use it as an explanation for 



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