LAWS OF GALTON AND MENDEL 179 



on; the sum of all those fractions equals one, or the 

 character of the individual in question. 



According to the law of ancestral inheritance 

 (either accepting the figures given by Galton or the 

 law as formulated in a slightly different form by other 

 biometrists) , the effects of heredity become inevitably 

 attenuated and variations abandoned to their fate are 

 doomed to disappear. Considered in this light, Gal- 

 ton's law constitutes a strong argument against the 

 definitive constancy of accidental variations produced 

 outside of the sphere of environmental influence. It 

 has been used by the opponents of natural selection 

 as a ready weapon. At the present day, however, a 

 renewed interest in Mendel's discoveries has cast some 

 doubts upon the accuracy of Galton's law, at least as 

 a universal law, and the line has not been drawn prop- 

 erly as yet between the cases to which it seems to apply 

 perfectly and the so-called Mendelian cases. 



Generally speaking, Galton's law seems to apply 

 more especially to reproduction within one race or 

 variety, while Mendel's laws, based upon experiments 

 in cross breeding, apply particularly to the characters 

 of hybrids. Mendel's observations were made over 

 half a century ago. Gregor Mendel, a monk, devoted 

 himself for many years to experiments on the crossing 

 of plants in the garden of the Briinn monastery. In 

 1866 he published the results of his experiments in an 

 obscure bulletin of the Natural History Society of 



