and Laboratory Methods. 2015 



CURRENT BOTANICAL LITERATURE. 



CHARLES J. CHAMBERLAIN, University of Chicago. 



Books for Review and Separates of Papers on Botanical Subjects should be Sent to Charles J. 

 Chamberlain, University of Chicago, Chicago, 111. 



Strasburger, Ed. Ueber Befruchtung. Bot. It will be remembered that Strasburger 

 Zeitung. 59: i-8, looi. • i • j , i r •,• • , 



m his paper on double fertilization^ 



insisted that in fertilization two processes should be recognized : the stimulation 

 to development and the mingling of ancestral qualities, the latter process being 

 the essential one, and the stimulation to development only providing the condi- 

 tions which make it possible to attain the advantages which result from a ming- 

 ling of ancestral plasma masses. 



Fluctuating variations do not furnish a starting point for the formation of 

 new species. It is the principal function of fertilization, through the mingling 

 of ancestral plasma masses, to keep the species characters constant. This view 

 agrees with that of Richard Hertwig and approaches that of Solms Laubach in 

 so far as the latter regards " so-called fertilization," or the fusion of hereditary 

 masses, as an essential element in fertilization, but Solms Laubach regards the 

 stimulation to development as an equally important attribute of fertilization. 

 Strasburger, however, defines the so-called fertilization definitely as the union of 

 the two hereditary plasma masses and believes that it was to insure this essen- 

 tially " generative fertilization " that in the course of phylogenetic development 

 the inability of the sexual cells to develop independently without fusion became 

 more and more marked. The term " generative fertilization " is used to designate 

 a union of ancestral plasmas in contrast with " vegetative fertilization," which is 

 merely a stimulus to development. Were it not for the fact that the two pro- 

 cesses occur simultaneously, the distinction would have been recognized long ago. 

 The term, fertilization, has often been loosely used in cases like many nuclear 

 fusions in fungi, where there is no union of hereditary masses but only a stimu- 

 lus to development. While Strasburger would be willing to admit that the stim- 

 ulus to development might be due to chemical or physical influences, he insists 

 that " generative fertilization " is not a purely chemical process. 



Winkler suggests that bastards might be produced by chemical fertilization. 

 Strasburger regards this as impossible, and believes that the essense of fertiliza- 

 tion lies in the union of organized elements. 



The view that the epigenesis of form is only an expression of the epigenesis 

 of chemical power, might, perhaps, appeal more to the physiologist than to the 

 morphologist, who has studied more deeply into the developmental history of 

 organisms. No doubt morphologists busied themselves too long with a one- 

 sided, mechanical view of ontogeny ; if the chemical theory does not in the same 

 way go beyond the mark, the two views, united, should be useful in extending 

 our knowledge. c. j. c. 



^ Strasburger, Ed. Einige Bemerkungen zur Frage nach der Doppelten. Befruchtung bei 

 den Angiospermen. Bot. Zeitung. 58 : 293-316, 1900. 



