460 THE BIOLOGICAL BASIS OF INDIVIDUALITY 



It is well known that the reactions of many animals towards other animals 

 are determined mainly by the sense of smell, which is very much more finely 

 developed in them than in man. This sense of smell plays evidently a great 

 role in the social-psychical relationships of certain insects. It is also appar- 

 ently by means of individual or family scents attaching to their young that 

 certain animals, for instance, a guinea pig mother, can distinguish their own 

 children from the children of others, and it is this factor which determines 

 the difference in their reactions towards their own offspring. In human 

 beings, this faculty is lost ; mothers no longer possess the ability to distinguish 

 babies from each other by the sense of smell. That human beings, too, possess 

 characteristic scents, however, is shown by the fact that dogs can thus readily 

 distinguish different individuals. 



As early as in 1879, Gustav Jaeger drew attention to the distinctive scents 

 differentiating human beings as well as human races. He maintained, further- 

 more, that different species, genera and classes of animals, each have their 

 own characteristic scents, different from those of other groups of animals. 

 As to the origin of scents, some of his conclusions were erroneous. He 

 believed, for instance, that the substances responsible for specific smells were 

 preformed already in the germ plasm ; similarly, he assumed that the sub- 

 stances, on which the specific sense of taste depends in various species of 

 animals, are present in their germplasm, and that these substances, together 

 with certain pigments which distinguish different races and species, represent 

 the specific constitution of the germplasm. However, it is not these substances, 

 themselves, which are preformed in the germplasm, but rather certain other 

 substances which, in the course of embryonal development, make possible 

 the formation of organs, whose metabolism is of such a nature that the 

 specific scents, tastes and pigments are produced. While, thus, the character 

 of specific scents is ultimately determined by the constitution of the germ 

 cells, the scents as such, represent derivatives of germ cell constituents. Jaeger 

 erred in still another direction. He did not differentiate between the inherited 

 individual or racial scents and others which are due to accidental, social 

 conditions. Traditional suggestions leading to emotional attitudes, the result 

 of certain phases in the social struggle, obscured, in this respect, his judgment. 



Subsequently, Correns drew attention to the importance of individual 

 differences in the scent of human beings, but it is especially Lohner who, 

 more recently, has analyzed experimentally the character of individual scents 

 and the reaction of dogs to them. According to Lohner, in human beings there 

 are regional smells distinctive of certain areas of the body, which are mainly 

 seated in the skin and which originate especially in the secretions given off 

 by the sebaceous glands. The different regional smells in the same individual 

 differ very much from one another, from a quantitative as well as from a 

 qualitative point of view, and these differences may be so pronounced that 

 even the human olfactory organ can differentiate them in the same individual. 

 On the other hand, a human being cannot recognize the scent of an individual 

 as a whole, while dogs, especially police dogs, can do so very readily. Accord- 

 ing to Lohner, such dogs, in addition, are able to recognize even individual 



