No. 587] CALIFORNIA DEER-MICE 689 



project. Without 'the generous opportunities afforded 

 me by the Scripps Institution, the work could never have 

 been undertaken. And of an importance only second 

 in order I must - mention the assistance rendered me 

 throughout these studies by the Museum of Vertebrate 

 Zoology at Berkeley. 



The resolution to which I have referred above formu- 

 lated four questions which were regarded as especially 

 worthy of consideration in the investigations contem- 

 plated. These were : 



1. To what extent do influences such as external condi- 

 tions, the exercise of organs or faculties, etc., which pro- 

 duce modifications of structure or function in the parent, 

 result in bringing about parallel changes in the offspring? 



2. If such changes are, in reality, found to reappear 

 in the offspring, do they constitute true examples of 

 heredity? 



3. Are the subspecies or geographical races of the sys- 

 tematic zoologists fixed, in the sense of being hereditary, 

 or do the differences by which they are distinguished 

 depend upon conditions which must act anew during the 

 lifetime of each individual ? 



4. If these subspecific characteristics are actually found 

 to 1 'breed true," do they owe their existence at the outset 

 to " mutations" or to the cumulative effect of environ- 

 mental influences, or to the mere fact of isolation, acting 

 in some way independently of those influences? 



To a large section of experimental breeders in this 

 country, to whom ' 1 genetics" is synonymous with Men- 

 delism, such a formulation of problems as this doubtless 

 seems hopelessly archaic. "What is the use of raising 

 all these dead issues," they will ask, "as if Weismann 

 and De Yries and Johannsen had never lived?" And as 

 for the question of subspecies, I suspect that some of our 

 critics would grant them no existence whatever, outside 

 the overwrought imagination of certain taxonomists. 



Those, however, who have read dispassionately such 

 able compilations of evidence as are offered us, for 



