CH. X] SUMMARY 143 



transmutation has occurred will be prevented by a proper 

 consideration of, firstly, the biological characters of the 

 organism in question as a whole and, secondly, the question 

 of the stability of the characters which distinguish it. 



With regard to the first of these questions, we have shown 

 in the sections dealing with Morphology, Fermenting power, 

 Virulence and Pathogenesis (Chapters IV-VII) the danger of 

 relying upon any one of these characters alone ibr the purpose 

 of identification or of classification. 



In the case of widely divergent types a single character 

 may sometimes suffice to distinguish one organism from 

 another but even in such a case, if that character is liable 

 under any circumstances to variation, it obviously cannot be 

 trusted as an infallible guide. 



The pathologist is in the same boat, in this respect, with 

 the ethnologist. Certain "race groups," e.g. the Teutonic, the 

 Mongolian, and the Negroid, though -conceivably derived from 

 a common anthropoid stock, are sufficiently differentiated to 

 be readily distinguished by a single character. For example, 

 the flaxen hair of the German, the matted black hair of the 

 Negro and the straight black hair of the Jap are sufficiently 

 characteristic of their respective race-groups. Such a dis- 

 tinction, however, breaks down between the races within 

 the groups themselves and other characters must then be 

 considered in addition. In some cases, again, the process of 

 differentiation is still incomplete, individuals approximating 

 now to one and now to another recognised type, and a con- 

 sideration of all the characters may still leave the observer 

 in doubt as to the correct classification. 



The ethnologist has learnt, moreover, that certain char- 

 acteristics are not to be regarded as racial in character. For 

 example — to return to our previous illustration — the pigtail 

 of the Chinaman and the shaven poll of the Thibetan priest, 

 the flowing locks of an Italian impressario and the tonsured 

 crown of a Romish monk, are not racial characters at all but 

 artificial modifications. They do, however, signify a certain 

 environment and training and this is precisely the case with 

 many of the variations which the pathologist meets with 



