Manchester Memoirs^ Vol. I. (1906), No. 11. 35 



2. Galton's Law : true of masses only. Statistical. 



3. The Law of Contribution : true of units. Physiological. 



APPENDIX B to p, 5. 



There is nothing, of course, in the word 'contribute' to 

 definitely signify that the thing which is contributed is the same 

 as that which contributes : in fact, in the everyday usage of the 

 term this is hardly ever the case. But it is reasonable to hold 

 that Galton's Law is the generalisation that like contributes like 

 and not unlike : and it is certain that Galton himself meant this, 

 as the last words of his illustration of particulate inheritance 

 readily shew " . . . . each piece of the new structure is derived 

 from a corresponding piece of some older one, as a lintel derived 

 from a lintel, a column from a column, a piece of wall from a 

 piece of wall." ('89, p. 8). 



APPENDIX C to A {[>) pp. 19— 23. 



There is an apparent paradox, in the ideas just expressed, 

 about which I think it is necessary to say a few words, in case 

 the reader should detect it himself and think that it had not 

 occurred to me. 



I have said that biometry deals with masses and Mendelism 

 with units ; but I have also said that the biometrician exceeds 

 his proper limits when he goes beyond the boundary of a unit, 

 while the Mendelian is concerned with the mutual properties of 

 numerous units : in other words the sphere of the biometrician 

 is within the unit while that of the Mendelian is outside it. 



