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duce such fruits are the English forcing cucumber, some varieties 

 of eggplant, Cellini and Charlamowski apples, Clairgeau pears, 

 navel oranges, seedless grapes, and bananas. Although it is im- 

 portant to know in these cases whether the fruit development has 

 occurred with or without pollination, such distinctions have 

 up to the present time not been carefully made, and all these 

 cases of fruit development without fertilization of the ovules 

 (regardless of whether pollination has taken place) have been 

 called parthenocarpy . 



Fertilization. — The steps in fertilization itself seem to be largely 

 chemical in nature. The attraction of the egg for the sperm is 

 often purely chemical. The eggs or the sex organs secrete acids 

 such as malic acid which exert a powerful influence over the sperms, 

 although the reasons for this attraction may be something more 

 than chemical. (From ultimate causes physiology is as far away as 

 any of the sciences.) When the sperm reaches the egg, its chief 

 function seems to be the initiation of a series of chemical reac- 

 tions which result in the development of the embryo. Lillie has 

 suggested that the sperm brings in a specific substance, "fertil- 

 izin," which starts these reactions. At any rate, fertilization by 

 the sperm is not always necessary for development of the embryo. 

 In all sections of the plant kingdom are to be found species which 

 develop regularly in this fashion without fertilization, including 

 Chora crinita, some varieties of apples, Taraxacum species, and 

 Antennaria. This development of the egg cell without fertiliza- 

 tion is called parthenogenesis, which in Marsilia may be obtained 

 by subjecting the spores to high temperatures. In fact parthe- 

 nogenesis is not uncommon in both the plant and animal kingdoms. 

 It is the normal method of reproduction in many insects and ro- 

 tifers, and Loeb devised means of stimulating artificially the eggs 

 of animals to develop parthenogenetically where normal fertili- 

 zation had been previously considered necessary. Even frog eggs 

 were made to develop without the influence of any sperm, and in 

 this way the famous " fatherless" frogs were obtained. Therefore, 

 there is still hope for those female members of the human species 

 who are struggling so hard for freedom from the slavery and 

 shackles of man. 



