in THE RENASCENCE OF SCIENCE 103 



the current belief in the separate creation of species. 

 He saw that this theory wholly failed to account 

 for the existence of abnormal forms, of adaptations 

 of the structure of organs to their work, of gradations 

 between living things, and other features inconsistent 

 with the doctrine of 'let lions be, and there were 

 lions.' His shrewd comment on the preformation 

 notion of development has been quoted (p. 20). 

 The substance of his argument in support of a 

 ' physical basis of life ' is as follows : ' When we 

 revolve in our minds the metamorphoses of animals, 

 as from the tadpole to the frog ; secondly, the 

 changes produced by artificial cultivation, as in the 

 breeds of horses, dogs, and sheep ; thirdly, the changes 

 produced by conditions of climate and of season, as 

 in the sheep of warm climates being covered with 

 hair instead of wool, and the hares and partridges 

 of northern climates becoming white in winter ; 

 when, further, we observe the changes of structure 

 produced by habit, as seen especially by men of 

 different occupations ; or the changes produced by 

 artificial mutilation and prenatal influences, as in the 

 crossing of species and production of monsters ; 

 fourth, when we observe the essential unity of plan 

 in all warm-blooded animals we are led to con- 

 clude that they have been alike produced from a 

 similar living filament.' The concluding words of 

 this extract make remarkable approach to the 

 modern theory that the essential elements of living 

 matter exist in the complex, semi - fluid, and 

 highly - active material known as protoplasm (p. 

 109). And, on this, Erasmus Darwin further re- 

 marks : ' As the earth and ocean were probably 



