Chapter VI 



HEREDITY 

 by Edward M. East 



DESCRIPTIONS of the properties of various chemical com- 

 pounds are found in Egyptian papyri; the science of 

 chemistry is no older than the American commonwealth. 

 Exact knowledge of the composition of substances and of 

 the transformations which they undergo was quite impossi- 

 ble before the atomic hypothesis was established by the 

 experimental demonstration of the Law of Definite and 

 Multiple Proportions. With the conception of the molecule 

 as the unit of matter identifiable in mass and of the atom as 

 the elementary unit, precise information concerning the 

 reaction of substances under known conditions was attain- 

 able, though no one has ever seen either molecule or atom. 

 A similar statement may be made about heredity. Doubtless 

 some of our paleolithic ancestors noticed whom the new 

 baby resembled, and formulated theories to explain the 

 situation. At all events, the ancient Egyptians and Baby- 

 lonians must have known something about inheritance, 

 for they left graphic records showing highly improved 

 breeds of domestic animals and of cultivated plants. Yet 

 the sum total of previous experience up to the middle of 

 the nineteenth century had yielded no more penetrating 

 solution of the mystery than the adage "Like produces 

 like," a proverb which, like many another, is not true. 

 There is something radically wrong with such a statement 

 as an expression of natural law, in view of the knowledge 

 that two snow-white rabbits may produce litter after 



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