yS [oiirnal of Comparative Neurology and PsyeJiology. 



of attention ; reason is a name for a host of particular capacities. "It 

 follows that an individual's status in any one function need not be 

 symptomatic of his status in others." Hence the fallacy of college en- 

 trance examinations as accurate measure of mental traits, and the folly 

 of using any one study, such as arithmetic, as the basis of promotion. 



In Chapters V and VI Professor Thorndike discusses the im- 

 portant questions of "Original and Acquired Traits," and "The Inher- 

 itance of Mental Traits." "What ancestry does is to reduce the vari- 

 ability of the offspring and determine the point about which they do 

 vary" (p. 48). There is no theoretical reason why we may not meas- 

 ure the variation and inheritance which determines family resemblance. 

 The author starts, of course, from the work of Galton, and discusses 

 the small amount of really scientific work which has been done in this 

 field. He does not mention the recent work on Mendel's law, which 

 certainly has a bearing. ' Nor is there any reference to the doctrine of 

 organic selection of Osborn, Morgan and Baldwin as offering a 

 possibility of mediation between the extreme views of the transmission- 

 ists and the non-transmissionists. 



Chapter VII is on "The Influence of the Environment." Here, 

 again, it is perfectly possible to measure the influence of change in 

 climate, food, school-training, friendship, sermon, occupation, etc. 

 But we must avoid the fallacy here "of attributing to training facts 

 which are really due to original nature or selection." The author 

 would substitute for such vague and indefinite terms as culture, discip- 

 line, training, practice, imitation, the conceptions of "(i) Furnishing 

 or withholding conditions for the brain's growth, and actions ; (2) Fur- 

 nishing or withholding adequate stimuli to arouse the action of which 

 the brain is by original nature or previous action capable ; (3) Rein- 

 forcing some and eliminating others of those activities in consequence 

 of the general law of selection in mental life" (p. 77). 



One of the most valuable Chapters in the book is Chapter VIII on 

 "The Influence of Special Forms of Training Upon General Abilities." 

 "Does the study of Latin or of mathematics improve one's general rea- 

 soning powers ? Does laboratory work in science train the power of 

 observation for all sorts of facts ?'" In other words, "How far does the 

 training of any mental function improve other mental functions ?" (p. 

 80). There is no doubt that there is some influence. The question 

 is, "To what extent and how" does this take place ? "Learning to do 

 one thing well has much less influence upon one's other abilities ' than ed- 

 ucational theorists would have us think. The general conclusion from 

 his own experiments is "that a change in one function alters any other 



