The Origin of Heredity 229 



influences which work upon the organism as a whole, 

 and reach the reproductive cells as well as the body tissues. 

 But to accomplish the transmission of specific modifica- 

 tions of particular parts, a very complex special mechan- 

 ism would be necessary, whereby the part affected in the 

 parent would impart some sort of special modification to 

 the germ-cells, which would in turn cause the same modifi- 

 cation of the same part in the offspring (cf. the address 

 of Sedgwick before the British Association, in Nature, 

 Sept. 21, 1899). 



It may also be suggested that such a complex mechanism 

 of transmission would be a highly specialized adaptation, 

 and if such a mechanism be necessary to Lamarckian 

 heredity, it would itself have to be accounted for without 

 such heredity. But the rise of complex adaptations is the 

 point at issue. 



§ 3. The Origin of Heredity 



This question takes on considerable importance in view 

 of recent discussion of the origin of heredity itself, in con- 

 nection with researches into variation. Heredity means, of 

 course, more or less lack of variation — what is called 



* breeding true ' to stock — from parent to offspring ; it is 

 the opposite of variability, which is departure from the 



* true ' or like. It has generally been assumed that hered- 

 ity, at least in the simple form seen in cell-division, — the 

 so-called daughter-cells being parts of the original mother- 

 cell, — was an original property of living matter, and 

 variation from the true was the phenomenon to account 

 for. Recently, however, the theory has been advanced by 

 Bailey {Plant Breeding, 1895, and especially Survival of 

 the Unlike, 1896) and Williams {Geological Biology; 



