HITCHCOCK: STUDY OF THE LOCAL FLORA 257 



make definite decisions as to the relations of facts discovered 

 is a natural one but may constitute a real menace in the future. 

 Having made a public statement as to the validity of a species 

 he may be reluctant to make a public retraction, even though 

 the evidence seems to require this. Rather than make a re- 

 traction he seeks for facts to support the original statement. 

 He welcomes such facts and magnifies their importance. Facts 

 tending to controvert the statement are excused or brushed 

 aside or given a minimum weight. He may enter that category 

 of scientists who assume the correctness of a theory and subse- 

 quently spend their time hunting for facts which will support 

 it. If the investigator can guard against this danger he has 

 accomplished much. If he can look upon his own work and 

 his own published statements with the same detached interest 

 and the same unbiased judgment that he does upon the work 

 of others, he has assumed the truly scientific attitude. One 

 does not like to be accused of drawing hasty conclusions. One 

 does not like to make a statement one day only to deny or 

 modify it the next. Nevertheless if he preserve an open mind 

 toward investigation, the worker will, I believe, find it neces- 

 sary to change his opinion as the facts accumulate. To ac- 

 complish results of the highest value he must establish an 

 hypothesis as a basis for the arrangement of his facts, but this 

 should remain tentative and elastic. The specialist on Aster 

 examines individuals, but the facts thus obtained must be clas- 

 sified and arranged if they are to be of taxonomic use. He soon 

 establishes in his imagination a series of groups which biologists 

 call species. To these groups he attempts to refer all the in- 

 dividuals he meets. It is not advisable to defer the establish- 

 ment of the specific concepts until the end of his investigations. 

 Theoretically this may be the best procedure, but practically 

 the worker can scarcely avoid forming preliminary ideas of 

 specific limitations. These preliminary concepts should form 

 a temporary hypothesis, to be changed from time to time as 

 the work progresses. The great majority of investigators are 

 able to keep their mental attitude in a responsive condition 

 up to the time they first publish the results of their work. It 



