482 VVATASE. [Vol. VI. 



must be considered to be the case in those eggs which are 

 produced parthenogenetically. 



The present paper is the preliminary statement of my con- 

 clusions on this subject, as based principally on my studies in 

 the line of work recently inaugurated by Auerbach/ who inves- 

 tigated the sexual substance of male and female organisms by 

 means of differential staining. Auerbach's method has been 

 appHed with a certain modification, in two special lines of study, 

 viz. the phenomena of spermatogenesis and of fecundation. 

 This afforded me the opportunity of tracing the micro-chemical 

 reaction of the male sexual cell through all stages of its trans- 

 formations from the moment of its origin in the seminiferous 

 gland of the paternal organism, until it ends in the formation 

 of a mature male pronucleus ready to unite with the female 

 pronucleus. The principal point which led to the writing of 

 the present paper consists in the fact that the micro-chemical 

 reaction of the sperm-mtcleiLS, wJiicJi is entirely dijferent from that 

 of the ovum-nucleus dttring the earlier stages of its existence, be- 

 comes essentially like that of the female pronucleus at the moment 

 of fecundation. Thus the distinction of sexes in the nuclei 

 of the germ-cells, which Auerbach has so clearly demonstrated 

 with specific stains in a number of cases, disappears completely 

 at the close of fecundation, so far as such a point can be deter- 

 mined by the micro-chemical test.^ The full bearing of this 

 fact upon the subject of our discussion, as well as the similar 

 observation of Lukjanow,^ I shall attempt to point out later. 



As has been truly said, the distinction of sex is probably 

 the most nearly universal single attribute or property of or- 

 ganized beings. According to one view, the difference of sex 

 is the absolute difference of material which enters into the for- 

 mation of the male and the female organism. There is also 



1 L. Auerbach, Zur Characteristik von Ei und Samen, Berl. Klin. Wochenschr., 

 1891, xxviii, 908; ijber eitten sexuellen Gegensatz in der Chromatophilie der Keim- 

 substa7izen, nebst Bemerkiingen zum Ban der Eier und Ovarien niederer Wir- 

 belthiere, Sitzungsber. der K. Preuss. Akad. d. Wiss. zu Berlin. XXXV, Heft 

 VII, 1891. 



'^ Some facts bearing on this subject may be found in the two following abstracts 

 of mine, The Origin of the Sertoli's Cell, American Naturalist, May, 1892 ; Ofi 

 the Significance of Spermatogenesis, American Naturalist, July, 1892. 



3 Lukjanow, Eitiige Bemerktingen ilber sexuelle Eletnente beiiii Spukourme des 

 Hundes, Arch. f. Mikr. Anat., Vol. 34, 1889. 



