312 STATISTICAL STUDY OF INHERITANCE 



read chapter xii. of J. T. Merz's invaluable History of European 

 Thought in the Nineteenth Century (vol. ii., 1903, pp. 548-626). 

 He traces the development of methods — e.g. : the investigations 

 of Gauss and Laplace on the theory of error ; he gives examples 

 of their application — e.g. the kinetic theory of gases ; and he 

 shows how Quetelet was practically the first to apply statistical 

 methods to human problems in his celebrated work Sur V Homme et 

 le Developpement de ses FacuUes, ou Essai de Physiaue sociale (1823). 



But " the first who seems to have fully grasped the Darwinian 

 problem from this (statistical) point of view is Mr, Francis 

 Galton, who in a series of papers, and notably in his well-known 

 works on Hereditary Genius (1869), and on Natural Inheritance 

 (1889), made a beginning in the statistical treatment of the 

 phenomena of Variation." " Mr. Galton's application of the 

 theory of error to the facts of distribution and variation 

 enabled him to bring method and order into such questions 

 raised by the Darwinian theorj^ as natural selection, regression, 

 reversion to ancestral types, extinction of families, effect of 

 bias in marriage, mixture of inheritance, latent elements, and 

 generally to prepare the ground for the combined labours of 

 the naturalist and the statistician " (Merz, p. 618). 



Among those who have followed Mr. Galton's lead the most 

 prominent and progressive worker is Prof. Karl Pearson, who 

 has published numerous important mathematical contributions 

 to the theory of evolution in the Transactions and Pro- 

 ceedings of the Royal Society since 1893, and in his journal 

 Biometrika. The reader who is not prepared for much 

 mathematics should consult the second edition of Pearson's 

 Grammar of Science. See also his Chances of Death and other 

 Studies in Evolution (2 vols., 1897). 



§ 3. ^ Hint of the Statistical Mode of Procedure 

 Some idea of the mode of procedure in dealing statistically 

 with the facts of inheritance may be got from the following 



