2 THE MODERN STUDY OF ZOOLOGY 



from theory to theory, without taking care to estab- 

 lish each before passing on to the next, without 

 assuring oneself that the foundation on which one 

 is building is secure. Then comes the crash ; the 

 last theory breaks down utterly, and on attempting 

 to retrace our steps to firm ground and start anew, 

 we may find too late that one of the cards, possibly 

 at the very foundation of the pagoda, is either 

 faultily placed or in itself defective, and that this 

 blemish easily remedied if detected in time has, 

 neglected, caused the collapse of the whole structure 

 on whose erection so much skill and perseverance 

 have been spent. 



Thus men of science find it well occasionally 

 to take stock, to look back for the moment instead 

 of forward, to assure themselves that their operations 

 since the last stock-taking have really resulted in 

 a gain, and to define accurately the nature and 

 extent of that gain. 



Science has been aptly compared to a globe, 

 similar to our own earth a globe with a solid hard 

 crust bounded by an irregular surface. The solid 

 crust represents ascertained facts, facts that have 

 been confirmed and stowed away in their proper 

 places ; the irregularity of its surface indicates the 

 unequal accumulation of facts in the various branches 

 of knowledge. The atmosphere by which the whole 

 globe is invested represents the world of speculation, 

 of theories an atmosphere heavily laden with germs 

 and particles of truth, but germs as yet immature, 

 particles whose position relative to the solid crust 

 is not yet a fixed and determined one. 



