CH. xxxix. LAMARCK. 429 



Lamarck on the Development of Animals, 1801. - 

 Meanwhile Lamarck published in 1801 a little work on the 

 ' Organisation of Living Bodies,' and in it he first suggested 

 that the different species of animals were not created separ- 

 ately, but had been gradually altered from a few simple living 

 forms, so that, in the course of long ages, there had sprung 

 up an immense variety of animals in the world. It must 

 be 1 remembered that Lamarck had chiefly studied plants and 

 the lower animals. We have seen how Goethe showed that 

 all plants are only altered stems and leaves : and the lower 

 animals, such as jelly-fish, snails, and worms, differ much 

 less from each other than the higher animals do. There- 

 fore Lamarck was very much struck with the difficulty there 

 was in settling which were distinct forms or species, and 

 which might have come from the same parent, and he con- 

 cluded that the only difference was that some had branched 

 off from the common stock earlier than others, and so had 

 become more unlike just as brothers and sisters are very 

 like each other, while distant cousins are much less liable to 

 have the same features and expression. 



The more we know of animals and plants, said Lamarck, 

 the more difficult we find it to settle which are related to 

 each other and which are not. Linnaeus had long ago 

 pointed out that among plants which are well known, such 

 as the willows in Europe, the cactuses in South America, 

 and the heaths and everlastings at the Cape, there are so 

 many kinds differing very little from each other that it is 

 impossible to say which ought to be considered as separate 

 species and which as the descendants of one kind of plant. 



Moreover, we know how much plants and animals are 

 sometimes altered even in a few years. For example, by 

 growing in a drier soil or up a high mountain, plants 

 become stunted and altered in many ways, while birds when 



