5o8 TEE POPULAR SCIENCE MONTHLY 



when he suddenly burst forth with one of those inspirations of infants : 

 "Oh, papa, suppose our cat had kittens in the oven, would they be 

 kittens or biscuits ? " Many biometrists would agree with papa that 

 the oven is not so important as the old cat. The more this group of 

 scientists studies mental defectives and bad boys the more evidence they 

 disclose that to get good biscuits you must have good dough, that the 

 dough out of which boys are made is more important than the " dough " 

 spent in bringing them up. 



Statistical inquiries will lay bare the great underlying causes at 

 work in modifying human development. They are essential to esti- 

 mating the relative importance of public questions which the com- 

 munity must settle, and they enable society to attack intelligently its 

 most vital problems. On the other hand, when we come face to face 

 with the question what shall we do with a particular child, statistics are 

 often woefully dumb. We may know that a town is seriously affected 

 by its unrestrained temptations to strong drink, and yet the particular 

 boy we are interested in may not be at all influenced by this temptation. 

 We may know that a hundred women successively admitted to the 

 reformatory at Elmira, N. Y., were all feebleminded, as was recently 

 discovered, and yet this does not settle the question whether or not the 

 girl we have before us is weakminded. The statistical cross-section 

 studies of groups must be supplemented by prolonged studies of the 

 same individuals before we shall be able to scientifically apply our 

 knowledge to particular cases. 



It is because the now well-known method of measurement devised 

 by Professors Binet and Simon, of Paris, is of importance in diagnosing 

 the mental development of a particular child that it has given so much 

 impetus to the study of childhood. Wlien one reads the literature on 

 the subject it is easy to get the impression that the diagnosis of mental 

 age begins and ends with the Binet tests. This is one of those popular 

 mistakes which is very disquieting to the scientists. Ever since the 

 first psychological laboratory was established in Leipzig in 1879, a 

 large part of the work in this science has borne directly or indirectly 

 upon the problem of mental measurement. The attempt of an inex- 

 perienced person to measure intelligence or to use the Binet scale with- 

 out some knowledge of this twenty years of investigation along similar 

 lines is likely to be more or less of a farce. Even the studies that have 

 been made the past five years of the Binet tests alone would fill a good- 

 sized volume. There are at least half a dozen materially different Eng- 

 lish translations and adaptations of these tests. In this situation a 

 parent had better trust the opinion of the school teacher as to his child's 

 mental development, than to depend upon a diagnosis by the Binet scale 

 which is made by a person inexperienced in psychology and in the use 

 of laboratory tests. A properly trained expert, however, can diagnose 



