216 LAMARCK AND DARWIN 



morphological orientation than it had even for the transcen- 

 dentalists, for he was lacking almost completely in the sense 

 for morphology. Lamarck's scientific, as distinguished from 

 his speculative work, was exclusively systematic, and it was 

 systematics of a very high order. He introduced many 

 reforms into the general classification of animals. He was 

 the first clearly to separate Crustacea (1799), and a little 

 later (1800) Arachnids, from insects. He reduced to a certain 

 orderliness the neglected tribes of the Invertebrates, and 

 wrote what was for long the standard work on their 

 systematics the Histoire naturellc dcs Aniinanx sans 

 Vertcbrcs (1816-22). His speculative work on biology is 

 contained in three publications, the small book entitled 

 Considerations snr r organisation dcs corps vivants (1802), the 

 larger work of 1809, the Philosophie zoologique, and the 

 introductory matter to his Animanx sans Vertcbres (vol. i., 

 1816). 



It is no easy matter to give in short compass an account 

 of Lamarck's biological philosophy. He is an obscure writer, 

 and often self-contradictory. 



In the first part of the PJiilosopJiic zcologiquc Lamarck is 

 largely pre-occupied with the problem of whether species are 

 really distinct, or do not rather grade insensibly into one 

 another. As a systematist of vast experience Lamarck knew 

 how difficult it is in practice to distinguish species from 

 varieties. " The more," he writes, " we collect the productions 

 of Nature, the richer our collections become, the more do we 

 see almost all the gaps filled up and the lines of separation 

 effaced. We find ourselves reduced to an arbitrary 

 determination, which sometimes leads us to seize upon the 

 slightest differences of varieties, and form from them the 

 distinctive character of what we call a species, and at other 

 times leads us to consider as a variety of a certain species 

 individuals a little bit different, which ethers regard as 

 forming a separate species." 1 



For Lamarck, as for Darwin later, the chief problem was 

 not the evolution and differentiation of types of structure, 

 but the mode of origin of species. 



Lamarck is at great pains to show how arbitrary are our 



1 Phil, zool,, ed. Ch. Martins, vol. i., p. 75, 1873. 



