68 THE METHOD OF DARWIN. 



ing unsuccessful efforts based on reasoning, 

 they go on to say, " We next thought that, if 

 care were nat taken in cutting off the tips 

 transversely, one side of the stump might be 

 irritated more than the other, either at first, or 

 subsequently during the regeneration of the 

 tip, and that this might cause the radicle to 

 bend to one side." They amputated some 

 radicles obliquely and some transversely, and 

 allowed them to grow perpendicularly. There 

 was little or no distortion at first; but after 

 two or three days, when the new tips began to 

 form, the distortion of the obliquely amputated 

 radicles became very conspicuous. The new 

 tip was probably formed obliquely, causing the 

 bending. Sachs probably " unintentionally am- 

 putated the radicles not strictly transversely " ; 

 and by not attending to this apparently insig- 

 nificant condition he produced confusion and 

 failed to make a discovery. 



This case is interesting not only because it 

 illustrates the difficulties that are met by the 

 individual investigator, but because it is a typ- 

 ical example of a very large proportion of con- 

 tradictions in results with which the literature 

 of science is burdened. The contradiction in 

 the results obtained by the two men was due, 

 not to errors of observation, but to neglect of 



