6 PROBLEMS OF GENETICS 



species is for example sometimes likened (see for instance Shar- 

 rock, loc. cit.) to the metamorphoses of insects, and it is to be 

 remembered that the search for the Philosopher's Stone by which 

 the transmutation of metals was to be effected had only recently 

 fallen into discredit as a pursuit. 



The notion indeed of a peculiar, fixed meaning to be attached 

 to species as distinct from variety is I think but rarely to be 

 found categorically expressed in prae-Linnaean writings. 



But with the appearance of the Systema Naturae a great 

 change supervened. Linnaeus was before all a man of order. 

 Foreseeing the immense practical gain to science that must come 

 from a codification of nomenclature, he invented such a system. 



It is not in question that Linnaeus did great things for us and 

 made Natural History a manageable and accessible collection of 

 facts instead of a disorderly heap ; but orderliness of mind has 

 another side, and inventors and interpreters of systems soon attri- 

 bute to them a force and a precision which in fact they have not. 



The systematist is primarily a giver of names, as Ray with 

 his broader views perceived. Linnaeus too in the exordium to 

 the Systema Naturae naively remarks, that he is setting out to 

 continue the work which Adam began in the Golden Age, to give 

 names to the living creatures. Naming however involves very 

 delicate processes of mind and of logic. Carried out by the light 

 of meagre and imperfect knowledge it entails all the mischievous 

 consequences of premature definition, and promotes facile 

 illusions of finality. So was it with the Linnaean system. An 

 interesting piece of biological history might be written respecting 

 the growth and gradual hardening of the conception of Species. 

 To readers of Linnaeus's own writings it is well known that his 

 views cannot be summarized in a few words. Expressed as they 

 were at various times during a long life and in various connexions, 

 they present those divers inconsistencies which commonly 

 reflect a mind retaining the power of development. Nothing 

 certainly could be clearer than the often quoted declaration of the 

 Philosophia Botanica, ''Species tot numeramus quot diversae 

 formae in principio sunt creatae," with the associated passage 

 "Varietates sunt plantae ejusdem speciei mutatae a caussa 



