FIELD STUDY 41 



their importance and significance. In a given case 

 the problem is therefore reduced to selecting the facts 

 for record, with a broad and deep comprehension 

 of the principles involved, a definite understanding 

 of the rules of the game, an appreciation of what is 

 probable and what is not probable ; or else making 

 mere random observations. All agree that the 

 latter alternative is worse than useless, and therefore 

 the only training which can make a geologist safe, 

 even in his observations, is to equip him with such a 

 knowledge of the principles concerned as will make 

 his observations of value." 



Early in field work one should learn that the 

 collection of specimens is not the primary aim of 

 excursions, that specimens are only one kind of 

 facts, but that field study should be devoted to the 

 accumulation of specimens, and to observations on 

 the habits, activities, interrelations, and responses 

 of animals, as well as to all facts, inferences, and 

 suggestions which are likely to be of use in the inter- 

 pretation of the problems studied. 



We sometimes hear that reflections upon the work 

 should be reserved for the return to the laboratory 

 or study. This advice seems to be based upon the 

 assumption that study in the field is not particularly 

 stimulating and suggestive. On the other hand de- 

 liberating interpret atively in the midst of the prob- 

 lems under consideration is one of the most favorable 

 conditions possible for the improvement of the quality 

 and quantity of one's work. It should be recalled in 

 this connection that Darwin and Wallace's evolu- 



