III.] 



ORGANIC STABILITY. 



27 



ances, each a distinct step in the improvement of one 

 or other of the three primary types, and there are or 

 may be in each of the three an indefinite number 

 of varieties in details, too unimportant to be subjects 

 of patent rights. 



The broad classes, of primary or subordinate types, 

 and of mere deviations from them, are separated by no 

 well-defined frontiers. Still the distinction is very ser- 

 viceable, so much so that the whole of the laws of patent 

 and copyright depend upon it, and it forms the only 

 foundation for the title to a vast amount of valuable 

 property. Corresponding forms of classification must 

 be equally appropriate to the organic structure of all 

 living things. 



Model. The distinction between primary and sub- 

 ordinate positions of stability will be made clearer by the 



FIG .1. 



help of Fig 1, which is drawn from a model I made. The 

 model has more sides, but Fig. 1 suffices for illustration. 

 It is a polygonal slab that can be made to stand on any 

 one of its edges when set upon a level table, and is 



