38 CHAKLES R. STOCK AED 



has very probably caused the degradation and even the elim- 

 ination of certain human groups; the extinction of several 

 ancient stocks has apparently followed very closely the ex- 

 tensive absorption of alien slaves. If one considers the 

 histories of some of the south European and Asia-Minor 

 countries from a strictly biological and genetic point of view, 

 a very definite correlation between the amalgamation of the 

 whites and the negroid slaves and the loss of intellectual and 

 social power in the population will be found. The so-called 

 dark ages followed a brilliant antiquity just after the com- 

 pletion of such mongrel amalgamation. Contrary to much 

 biological evidence on the effects of hybridization, racially 

 prejudiced persons, among them several anthropologists, deny 

 the probability of such results from race hybridization in man. 

 There is no doubt that unstable individuals with structural 

 and functional disharmonies arise from crosses between con- 

 trasted breeds of dogs, and probably the same conditions to 

 lesser or greater degree result from hybridization among other 

 mammals, including man himself. Certainly no answer to 

 these debatable and very important questions can be scien- 

 tifically arrived at by any method other than careful experi- 

 mentation on higher mammals, and, in the light of such 

 experiments, an impartial study of the unregulated human 

 results. 



The pure breeds selected for hybridising and their strongly 

 contrasted characters. Many biologists and workers in the 

 medical sciences, as well as specialists in endocrinology and 

 genetics, have only limited knowledge of the detailed charac- 

 teristics of the various dog breeds. In spite of this fact, it is 

 scarcely in line with our present purpose to devote space to a 

 detailed survey of the characteristics of all the breeds we have 

 employed. It seems much more desirable to describe the char- 

 acters of the different pure breeds in connection with par- 

 ticular experiments aimed at an analysis of the nature and 

 significance of these characters. Proceeding in this manner 

 we are quite certain that the reader will be able to appreciate 

 the experiments and their results without personal acquaint- 



