44 FATHERS OF BIOLOGY. 



like a coppersmith, who for cheapness makes a spit-and- 

 a-candlestick in one. 1 It is only when this is impossible 

 that she uses one organ for several functions." 



In conclusion, we may say that the great Stagirite 

 expounded the true principles of science, and that when 

 he failed his failure was caused by lack of materials. 

 His desire for completeness, perhaps, tempted him at 

 times to fill in gaps with such makeshifts as came to 

 his hand; but no one knew better than he did that 

 " theories must be abandoned unless their teachings 

 tally with the indisputable results of observation." 2 



2 "De Gener.," iii. 10, quoted by Dr. Ogle. 



