THE AMERICAN NATURALIST [Vol. LV 



THE TURKEY AS A SUBJECT FOR EXPERIMENT 



Experiments with our native vertebrates offer many diffi- 

 culties not encountered when dealing with domestic animals. In 

 the field of genetics especially, while domestic animals continue 

 to furnish enticing problems, it is not strange, therefore, that 

 they practically monopolize the attention of students. No one 

 can foresee how far work of this kind will proceed but it seems 

 probable that some important phases of the subject of variation 

 never can be elucidated by the study of domestic animals alone. 

 Hence it would be very desirable to work with wild forms 

 wherever this is practicable. This would be especially interest- 

 ing for study of the significance of the intergrading subspecies 

 or "geographic race" which is found so widely in nature but 

 which appears to have no recognizable counterpart in the ordi- 

 nary variations of domestic animals. 



The so-called subspecies perhaps needs no introduction even 

 to biologists who do not have first-hand acquaintance with it, 

 but the extent to which it features in the fauna of the world 

 seems scarcely realized even among those who are quite familiar 

 with it. Within the memory of the present generation, the ulti- 

 mate division of classification was the species and attempts to 

 divide this into races or varieties were often looked at askance as 

 probably indicating an over-weening desire to multiply names 

 and magnify differences of no phylogenetic significance. In 

 wrestling with the question ''What is a species?" many were 

 led to eschew classification entirely and contented themselves 

 with the knowledge that no two individuals were alike and the 

 belief that efforts to associate them were futile. JNIeanwhile, in 

 spite of beadshaking in various quarters, "hair-splitting" has 

 continued until at present nothing is clearer than that the sub- 

 species is a reality constituting a widespread and obvious evi- 

 dence of active contemporary change in organisms, not only in 

 single individuals but in groups of individuals. 



In ornithology and in mammalogy, at least, the old-fashioned 

 species in the vast majority of cases is found to be a composite 

 or a mosaic definitely divisible into units connected by graded 

 series and having a plain relation to geographic distribution. 

 A species of continental distribution in North America, for ex- 

 ample, may have one subspecies in the east, one in the north and 

 several in the south and west each occupying a limitable area 

 and each characterized throughout its range by certain features 



