NATURAL HISTORY OF THE EIGHTEENTH CENT. 397 



which have terminated their development at a comparatively low point 

 in the scale. Here is the table : 



Vermes 



Insecta 



I 

 Arachnida 



Crustacea 



Annelida 



Cirrhipedia 



I 

 Mollusca 



Infusoria 



Polypes 

 I 



Radiata 



Fishes 

 Reptiles 



Amphibious, Mammalia 

 Cetacea 



Clawed Mammalia 



In another part of his work Lamarck points out that in science the 

 only positive truth obtainable by man is the knowledge of facts that 

 is, of the actual succession of phenomena. Beyond there is room for 

 any amount of uncertainty; but nevertheless certain inferences, theories, 

 opinions, etc., as to the actual connection and causes of phenomena, 

 are much more probable than others. He places two conclusions 

 before the choice of his readers : the one, that which had up to his 

 time been in vogue, namely, that the Author of Nature had abruptly 

 created animals in species having organizations determined and in- 

 variable in all their parts, and being compelled therefore to live in 

 such climates and places only as were compatible with that organiza- 

 tion ; the other, which is his own conclusion, that the Supreme had 

 created such an order of things as gives rise by degrees to one species 

 of animals after another, beginning from the simplest or most imper- 



