330 THE BEGINNINGS OF CAUSAL MORPHOLOGY 



achieved by Roux's fello\v-\vorkers in the field of causal 

 morphology. As D. Barfurth points out, 1 the years 1880-90 

 saw a general awakening of interest in experimental 

 morphology, and it is hard to say whether Roux's work 

 was cause or consequence. " There fall into this period," 

 writes Barfurth, "the experimental investigations by Born 

 and Pfliiger on the sexual difference in frogs (1881), by 

 Pfliiger on the parthenogenetic segmentation of Amphibian 

 ova, on crossing among the Amphibia, and on other 

 important subjects (1882). In the following year (1883) 

 appeared two papers of fundamental importance, by E. 

 Pfliiger and \V. Roux : Pfliiger publishing his researches 

 on 'the influence of gravity on cell -division,' Roux his 

 experimental investigations on 'the time of the determina- 

 tion of the chief planes in the frog-embryo.' ... In the 

 same year appeared A. Rauber's experimental studies 'on 

 the influence of temperature, atmospheric pressure, and 

 various substances on the development of animal ova,' 

 which have brought many similar works in their train. 

 The following year (1884) saw a lively controversy on 

 Pfliiger's gravity-experiments with animal eggs, in which 

 took part Pfliiger, Born, Roux, O. Hertwig and others, and 

 in this year appeared work by Roux dealing with the 

 experimental study of development, and in particular giving 

 the results of the first definitely localised pricking-experi- 

 ments on the frog's egg (in the Sf///<\\: (icsc/l. /. ratci'l. 

 K/i/fnr, 1 5th Feb. 1884), also the important researches of 

 M. Nussbaum and Grubcr (followed up later by Yerworn, 

 Hofer and Balbiani) on Protozoa, and other experimental 

 work" (pp. xi.-xii.). 



In 1 888 appeared a famous paper by W. Roux,- in which 

 he described how he had succeeded in killing by means of 

 a hot needle one of the two first bias torn eres of the frog's 

 egg, and how a half-embryo had developed from the 

 uninjured cell. Some years before :; he had enunciated, at 

 about the same time as \\Vismann, the viVw that development 



1 "\Vilhelm Roux xinn 60. Cicburtsta-c,'' Arch. f. /i>/Av.-J/<v//., xxx. 

 /', .v/.\r /////"/ //cr 1'rof. AVv/.r, 1't. i, 1910. 



Vin limv's Aichir, cxiv., I 888. First announced in Sept. 1887. 

 ' Ucbcr die Bedeutung der Kernteilungsfiguren^ Leipzig, 



