622 



SCIENTIFIC THOUGHT. 



biological research. 1 He has thus put into the hands of 

 naturalists an instrument wherewith to describe graphi- 

 cally the observed facts of variation and other allied 



1 A considerable literature has 

 already accumulated in this novel 

 branch of exact inquiry. The 

 complete list of it is given in a 

 pamphlet by Georg Duncker, en- 

 titled 'Die Met bode der Variations- 

 statistik' (Leipzig, 1899). From 

 this list (p. 60) it will be seen that 

 one of the earliest workers in the 

 field of biological statistics was 

 the botanist F. Ludwig, whose 

 ' Abschnitte der Mathematischen 

 Botanik' have appeared in various 

 periodicals abroad since the year 

 1883. The philosopher, however, 

 to whom we are most indebted for 

 the mathematical foundations of the 

 whole theory, is, as noted above, 

 Prof. Karl Pearson, whose "Con- 

 tributions to the Mathematical 

 Theory of Evolution" have been 

 appearing since the year 1893 in 

 the Trans, of the Royal Society. 

 Very helpful abstracts of these 

 contributions, covering a large 

 field of mathematical theory, and 

 containing elaborate discussions of 

 many of the terms recently in- 

 troduced into biological science, 

 such as regression, reversion, in- 

 heritance, panmixia, selection, &c., 

 will be found in the Proceedings of 

 the Royal Society (1893, onwards). 

 Also in his collected essays, "The 

 Chances of Death and other Studies 

 in Evolution '(2 vols., 1897); and, 

 lastly, in the later chapters of the 

 second edition of his ' Grammar of 

 Science' (1890). From the latter it 

 will be seen what far-reaching infer- 

 ences may eventually be drawn 

 from the quantitative treatment 

 and mathematical discussion of 

 biological data ; notably the results 

 so far gained "lead us to consider 

 variation as a permanent attribute 

 of living forms, which can hardly 



have been substantially modified 

 since the beginnings of life. In the 

 same manner we find heredity in- 

 timately associated with variation 

 in the individual, and not differing 

 very substantially as we pass from 

 one character to a second, or from 

 one to another form of life. We 

 conclude that variation and inherit- 

 ance rather precede than follow 

 evolution ; they are, at present, one 

 fundamental mystery of the vital 

 unit" (p. 502). Prof. Pearson, 

 whose training was that of a 

 mathematician and a lawyer, ap- 

 proached the problems of biology 

 from the exact point of view, and 

 it is interesting to see how. in many 

 ways, he comes to results similar to 

 those arrived at by one of the other 

 great representatives of modern 

 biological research, Mr Wm. Bate- 

 son. See his ' Materials for the 

 Study of Variation, treated with 

 especial regard to the discontinuity 

 in the Origin of Species ' (1894). If 

 I understand him rightly, his re- 

 searches have led him to the con- 

 clusion that variation cannot be 

 the work of natural selection, since 

 he has given " such evidence as to 

 certain selected forms of varia- 

 tions " as to afford " a presumption 

 that the discontinuity of which 

 species is an expression has its 

 origin, not in the environment, nor 

 in any phenomenon of adaptation, 

 but in the intrinsic nature of 

 organisms themselves, manifested 

 in the original discontinuity of 

 variations " (p. 567). This " dis- 

 poses, once and for all, of the 

 attempt to interpret all perfection 

 and definiteness of form as the 

 work of selection. ... It suggests, 

 in brief, that the discontinuity of 

 species results from the discontinu- 



