130 BIOLOGY AND ITS MAKERS 
details, and they made it possible for the observations and 
discoveries of others to be understood and to take their place 
in the great system of which he was the originator. The 
effect of the last step was to direct the attention of naturalists 
to species, and thereby to pave the way for the coming con- 
sideration of their origin, a consideration which became such 
a burning question in the last half of the nineteenth century. 
REFORM OF THE LINNEAN SYSTEM 
Necessity of Reform.—As indicated above, the classifica- 
tion established by Linnzus had grave defects; it was not 
founded on a knowledge of the comparative structure of 
animals and plants, but in many instances upon superficial 
features that were not distinctive in determining their position 
and relationships. His system was essentially an artificial 
one, a convenient key for finding the names of animals and 
plants, but doing violence to the natural arrangement of those 
organisms. An illustration of this is seen in his classification 
of plants into classes, mainly on the basis of the number of 
stamens in the flower, and into orders according to the number 
of pistils. Moreover, the true object of investigation was 
obscured by the Linnean system. The chief aim of bio- 
logical study being to extend our knowledge of the structure, 
development, and physiology of animals and plants as a 
means of understanding more about their life, the arrange- 
ment of animals and plants into groups should be the out- 
come of such studies rather than an end in itself. 
It was necessary to follow different methods to bring 
natural history back into the line of true progress. The first 
modification of importance to the Linnzan system was that 
of Cuvier, who proposed a grouping of animals based upon 
a knowledge of their comparative anatomy. He declared 
