AN ATTEMPT AT A PHYSICO-CHEAIICAL EXPLANA- 

 TION OF CERTAIN GROUPS OF FLUCTUATING 

 VARIATION 



JACQUES LOEB and MARY MITCHELL CHAMBERLAIN 



There is a general tendency to visualize the factors which 

 determine the hereditary characters as specific chemical com- 

 pounds. If we wish to carry this view (with which we sympa- 

 thize) beyond the limit of a vague statement, we must either 

 try to establish the nature of these compounds by the methods 

 of the organic chemist, or we must use the methods of general 

 or physical chemistry and try to find numerical relations by 

 which we can identify the quantities of the reacting masses or 

 the ratio in which they combine. Attempts in this direction 

 have been made by the suggestion of Loeb^ that phenomena of 

 growth belong in the group of auto-catalytic processes, and by T. B. 

 Robertson's- and Ostwald's investigations supporting and enlarg- 

 ing this idea; by A. R. Moore's' attempt to show that in hybrids 

 the velocity of development of the dominant character is slower 

 than in the pure dominant breed; and by Loeb and Ewald's^ 

 proof that all the embryos of Fundulus have practically the same 

 rate of heart beat at the same temperature. Since our ne^ 

 experiments are a sequence of this last mentioned paper, we 

 may briefly discuss its contents. 



■^J. Loeb. Ueber den chemischen Character des Befruchtungsvorgangs 

 Roux's Vortrage und Ausatze, Leipzig, 1908. Biochem. Ztschr., 2, 34, 1906. 



2 T. B. Robertson. Roux's Archiv, 25, oSl, 1908; 26, 108, 1908; 37, 497, 1913. 

 Am. Jour. Ph3^sioL, 37, 1, 1915; Robertson and Wasteneys, Roux's Archiv, 37, 

 485, 1913; Wo. Ostwald. Ueber die zeitlichen Eigenschaften der Entwicklungs- 

 vorgange, Leipzig, 1908. 



3 A. R. Moore. Roux's Archiv, 34, 168, 1912. 



* J. Loeb and W. F. Ewald. Biochem. Ztschr., 58, 177, 1913. 



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