PAKTHENOGENESIS 



AMIDST the all-absorbing discussion of the problems 

 which have arisen out of the general acceptance among 

 biologists of the law of evolution, the phenomenon of 

 Parthenogenesis which, previously to Mr. Darwin's 

 work on the Origin of Species, excited the interest 

 and called forth the investigations of observers in 

 much the same manner as his theory has done of late 

 years, has met with a reverse of fortune and fallen 

 into a subordinate rank of popularity. The dis- 

 tinguished naturalist, however, who fifteen years ago 

 gave so stunning a blow to current theories of the 

 reproductive process, by demonstrating the occurrence 

 in moths and bees of what he designated as "true 

 parthenogenesis" that is to say, the development, 

 without impregnation, of an ovum capable of being 

 impregnated has not let the subject drop. Professor 

 Siebold has made further experimental researches, 

 establishing again, and on a larger basis, his former 

 conclusion, and adding at least one new fact of great 

 general importance for the understanding of the 

 process of sexual reproduction. Although upon its 

 first appearance in 1856, the conclusion arrived at in 

 his Wahre Parthenogenesis was admitted by almost 



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