ERASMUS DARWIN, HERBERT, FREKE. IIQ 



Descent. In 1795 he publislied, under the title of " Zoono- 

 mia," a scientific work in which he expresses views very 

 similar to those of Goethe and Lamarck, without, however, 

 then knowing anything about these two men. It is evident 

 that the Theory of Descent at that time pervaded the intel- 

 lectual atmosphere. Erasmus Darwin lays great stress upon 

 the transformation of animal and vegetable species by their 

 own vital action and by their becoming accustomed to 

 changed conditions of existence, etc. Next, W. Herbert, in 

 1822, expressed the opinion that species of animals and plants 

 are nothing but varieties which have become permanent. 

 In like manner Grant, in Edinburgh, in 1826, declared that 

 new species proceed from existing species by continued 

 transformation. In 1841 Freke maintained that all organic 

 beings must be descended from a single primitive type. In 

 1852 Herbert Spencer demonstrated minutely, and in a very 

 clear and philosophic manner, the necessity of the Doctrine 

 of Filiation, and established it more firmly in his excellent 

 " Essays," which appeared in 1858, and in his " Principles of 

 Biology," which was published at a later date. He has, at 

 the same time, the great merit of having applied the theory 

 of development to psychology, and of having shown that the 

 emotional and intellectual faculties could only have been 

 acquired by degrees and developed gradually. Lastly, we 

 have to mention that in 1859 Huxley, the first of English 

 zoologists, spoke of the Theory of Descent as the only 

 hypothesis of creation reconcilable with scientific physiology. 

 The same year produced the " Introduction to the Flora of 

 Tasmania," in which Hooker, the celebrated English 

 botanist, adopts the Theory of Descent, supporting it with 

 important observations of his own. 



