SOME EFFECTS OF TEMPERATURE UPON 

 GROWING MICE, AND THE PERSISTENCE 

 OF SUCH EFFECTS IN A SUBSE- 

 QUENT GENERATION 1 



DR. FRANCIS B. SUMNER 

 Woods Hole, Mass. 



1 must preface my remarks by an apology for coming 

 before you with some results which have already been 

 published pretty fully within the past year. 2 My appear- 

 ance here may seem the more unwarranted in view of the 

 limited amount of evidence which I am about to offer 

 upon those subjects which form the focus of attention at 

 this meeting, namely heredity and evolution. However, 

 aside from the fact that I am acting at the instance of our 

 president, I will say two things in my own defense. 

 First, the results which I offer, meager as they doubtless 

 are, appear to be the only ones of just this sort which are 

 in evidence at present. 3 And secondly, I am bold enough 

 to believe that I have developed a promising method of 

 attacking a few of the many knotty problems which are 

 bound up together in the time-honored question: Are 



l Eead before the American Society of Naturalists, December 30, 1910. 



2 "Some Effects of External Conditions upon th • White Mouse," Journal 

 of Experimental Zoology, August, 1909. "The Reappearance in the Off- 

 spring of Artificially Produced Parental Modifications." American Nat- 

 uralist, January, 1910. "An Experimental Study of Somatic Modifica- 

 tions and their Keappearanee in the Offspring." Archiv fur Entwicllungs- 



ing paper, entitled 'Der Stand der Frage nach der Vererbung erworbener 

 Eigenschafton" (Fnrtscliritto der naturwissenschaftlichen Forschung, Bd. 

 II. 1910). From this T learn that some of the more important features of 

 my results have been obtained by Pndbram, in the course of experiments 

 upon rats, conducted at about the same time as my own. I have not yet 



dispel any doubts as to the statistical significance of my own figures, what- 

 ever interpretation we may choose to give them. 



90 



