304 



SCIENTIFIC THOUGHT. 



the existing knowledge of the early development of 

 the germs of animals by discovering the ovum in the 

 body of the mammalia before fructification, and by this 

 and other discoveries secured his claim to be considered 

 the greatest embryologist of his own age, and perhaps 

 of all time. He goes on to examine to what extent the 

 morphological differences which the animal kingdom ex- 

 hibits in its various members can be taken as a guide to 

 the genetic differences in the growth and development of 

 the higher organisms. He, in fact, tried to ascertain 

 how far the facts of classification throw a light on the 

 facts of development, how far the changing embryo of 

 the higher animal gradually passes through the- permanent 

 forms of the lower animals. He combats the idea that 

 the classification or morphological arrangement can be 

 uni- serial i.e., brought into one continuous line or order. 



his researches. He wishes to dis- 

 tinguish carefully between facts 

 and theory, and is very cautious 

 as to the latter, a trait which 

 runs through all his writings. It 

 is also very interesting to see how 

 iu his biography of Cuvier (post- 

 humously published by Stieda) he 

 considers it a merit of that great 

 naturalist not to have indulged 

 in genetic theories. "It is evi- 

 dent that Cuvier in his youth had 

 also a genetic system in view, such 

 as Oken afterwards followed up, 

 but that he must soon have found 

 out that this task was unattainable 

 for him. He abandoned it, and 

 sought rather to draw from the 

 manifoldness of the formed pro- 

 duct inferences regarding the con- 

 ditions of its genesis. Thus he 

 arrived at the teleological concep- 

 tions which he developed on vari- 

 ous occasions. German naturalists 



drew from all this, especially in 

 the age of Schelling's ' Natur-phil- 

 osophie,' the conclusion that Cuvier 

 was not a philosophical mind. To 

 me it seems that we recognise in it 

 Cuvier's desire for clearness. He 

 dropped the higher task because 

 he found that it would not lead 

 him to clear views" ('Lebensge- 

 schichte Cuvier's von K. E. von Baer,' 

 ed. Stieda, 1897, p. 72). English 

 readers, to whom the genetic view 

 has only become familiar since 

 Darwin or perhaps Lyell, will find 

 with astonishment how in the 

 writings of Baer, before Lyell and 

 even before the appearance of 

 Cuvier's final system, genetic ideas 

 were thought to be prevalent, and 

 were criticised elaborately and re- 

 ceived with the utmost caution 

 even by the great propounders of 

 the doctrine of development. 



