THE INDIVIDUALITY-DIFFERENTIAL AND ITS 

 MODE OF INHERITANCE 



PROFESSOR LEO LOEB 



(From the Department of Comparative Pathology, Washington Uni- 

 versity School of Medicine, St. Louis, Mo.) 



In a preceding communication we have shown that all 

 the tissues of an individual have in common a chemical 

 characteristic through which they differ from other indi- 

 viduals of the same species. This characteristic may be 

 designated as the individuality-differential. It is prob- 

 able that in the circulating body fluids these individuality- 

 differentials or substances specifically adapted to them 

 are likewise present. The interaction of cells and sub- 

 stances which possess the same individuality differential 

 leads to the production of autosubstances which are re- 

 sponsible for various conditions of tissues. But if, 

 through transplantation, the individuality-differentials 

 become converted into syngenesio-, homoio- or hetero- 

 differentials toxic substances are produced, the syn- 

 genesio-, homoio- or heterotoxins which lead to tissue 

 reactions of different kinds as we have described in the 

 preceding communication. 



In the process of fertilization usually two homoio-dif- 

 ferentials combine to form a new individual. Through 

 transplantation of tissue it is possible to determine 

 whether the individuality-differential of the child is iden- 

 tical with the individuality-differential of one of the two 

 parents or whether its character is intermediate. If the 

 inheritance of the individuality-differential should be- 

 have like a simple Mendelian monohybrid character, all 

 the offspring of the first generation would have the same 

 individuality-differential and the individuality-differ- 

 ential of one of the two parents would probably dominate. 

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