INCOMPETENCY OF WEISMANN'S THEORY 139 



separate and independent individuals, some of which have for 

 centuries retained properties of one order, some properties of 

 another to conceive the germ cell as a colony of individual 

 living beings, for this is what the theory demands. 1 



Driesch's Demonstration of the Incompetency of the Theory. 

 But it may be urged, what is the use of all this argument to 

 kill a theory already dead ? For dead it is, so far as regards 

 the ids, and Weismann's theory without the ids is like Shagpat 

 without the identical. The brilliant observations of Driesch, 2 

 abundantly confirmed as they have been by others, foremost 

 among whom must be mentioned Professor E. B. Wilson 3 

 of Columbia, and T. H. Morgan 4 of Bryn Mawr, show that 

 the conception is untenable. If in a segmenting ovum we find 

 that normally each of the blastomeres or primitive segmenta- 

 tion cells gives rise to one special series of organs or tissues, but 

 if nevertheless the ovum of sundry animals can have its cells 

 shaken apart at the two-, four-, eight-, and even sixteen-cell 

 stage, and each separated cell can be found capable of develop- 

 ing into an entire if dwarfed individual, then obviously, each 

 time the nucleus segments there is no passage into the daughter 

 nuclei of particular series of ids destined to lead to the develop- 

 ment of one particular region of the body. Rather the varia- 

 tion in structure of the different tissues must be, to employ 

 Driesch's words, " a function of their relative position " (ihre 

 prospective Bedeutung ist eine Function des Ortes). The exist- 

 ence of these hypothetical ids is absolutely disproved. I dwell 

 upon this theory because here I want more especially to 

 discuss, on account of its importance from a medical point of 

 view, this matter of the inheritance or non-inheritance of acquired 

 characters. I hope that I have proved to you that the ground- 

 work upon which the negative view is based is of proved un- 

 soundness. The fact that a theory by which a position is sup- 

 ported falls through does not, it is true, afford proof that the 

 position is wrong, but when we find that the dictum of non- 



1 For a fuller discussion of the weak points in the Weismann-Roux Theory, 

 regarded from an embryological aspect, vide Wilson, The Cell in Development 

 and Inheritance, New York, Macmillan, 1898, and Creswell Shearer, Montreal 

 Medical Journal, May 1901. 



2 Driesch, Zeitsch. f. wissenschaft. Zoologie, liii., 1892, and lv., 1893, and 

 Archivf. Entwickelungsmechanik, 1900, p. 361; ibid. p. 411. 



3 E. B. Wilson, Journal of Morphology, viii., 1893, p. 579. 



4 T. H. Morgan, Anatom. Anzeiger, x., 1895, p. 19. 



