Januaky 8, 1909] 



SCIENCE 



53 



falls short of the best attainable. The 

 scholarly teacher, with the genuine passion 

 for making scholars, is fortunate indeed if 

 he combines with it such broad sympathy 

 and good sense that his pupils will come to 

 him for advice on homely, everyday ques- 

 tions; for the influence thus gained doubt- 

 less reaches farther than we can possibly 

 know. For the teacher of science, who 

 more than his colleagues in other depart- 

 ments of learning, has the opportunity to 

 lead the thoughts of his pupils by an occa- 

 sional judicious word toward a better ap- 

 preciation of the orderliness of that which 

 we do know, and of the vastness of that 

 which is beyond our ken, the privileges as 

 well as the responsibilities are especially 

 great. 



The teacher's career is one of some sacri- 

 fice. Let us admit it, and admit also that 

 it may not be undertaken by those who have 

 not aptitude and liking for it, for these are 

 both indispensable to success. But let us 

 remember, too, that it is truly a noble call- 

 ing, accorded a dignified standing in our 

 communities; that it means for those who 

 enter upon it an association with scholars 

 and a share in those affairs which we believe 

 make for advancement of our race ; that its 

 rewards in the way of recognition among 

 scholars, and in the occasional spontaneous 

 expressions of appreciation on the part of 

 pupils, as well as in the lasting friendships 

 formed, are not unworthy to be placed 

 beside the more striking and tangible finan- 

 cial successes of other professions. Let us 

 recall that the advancement of our sciences 

 must always depend in a large measure 

 upon the maintenance of a high type of 

 teacher, as well as of teaching, for which 

 we need able, broad-minded men, not those 

 who are merely indisposed to adopt some 

 other profession; and to this end let us 

 foster an interest in the teacher's career on 

 the part of more of those to whom those 



traits of mind and character which make 

 for success in this honorable profession 

 have been freely given. 



Heney p. Talbot 

 Massachusetts Institute of Technology 



RECENT RESEARCHES ON THE DETER- 

 MINATION AND HEREDITY OF SEX^ 



I. STATEMENT OF THE PROBLEM 



Despite certain technical difficulties, the 

 subject of sex-production has seemed to me 

 to be an appropriate theme for this occa- 

 sion for two reasons. The phenomenon of 

 sex is so nearly a universal one that it 

 may be assumed to make some appeal to 

 the interest of biologists in every field of 

 inquiry. Secondly, although the physi- 

 ological meaning of sex still remains in 

 many respects enigmatical, it may fairly 

 be said that substantial advances in the 

 analysis of the mechanism of sex-produc- 

 tion are being made by experimental and 

 cytologieal research. It is not my inten- 

 tion to consider at this time the possible 

 significance of sexual reproduction or the 

 physiological and cytologieal problems in- 

 volved in the phenomena of fertilization. 

 My discussion will be confined mainly to 

 the more recent of the researches that have 

 thrown light on the questions of sex-de- 

 termination and sex-heredity. Does sex 

 arise, as was so long believed, as a response 

 of the developing organism to external 

 stimuli? Or is it automatically ordered 

 by internal factors, and if so, what is their 

 nature? 



It will be well at the outset to remove 

 any possible obscurity from our definition 

 of the problem. Every form of heredity 

 —and sex-production, broadly speaking, is 

 unquestionably a phenomenon of heredity 

 — is in one sense a response of the develop- 

 ing organism to external stimuli. The 



' Address of the vice-president and chairman of 

 Section F — Zoology — of the American Association 

 for the Advancement of Science, Baltimore, 1908. 



