TliK CAVKNDISH LECTURE 5 



mtclligcnce is difficult indeed to estimate, and what man calls 

 intelligence is often obedience to human wants, and not the 

 obstinacy and self-determination which would actually aid these 

 animals in a free struggle for existence. The male of a race of 

 dogs I breed is ever alert, eminently companionable, and can be 

 taught to do all sorts of tricks — he is at once supposed to be very 

 intelligent ; the female is apparently relatively inert, learns few 

 tricks, and shows no special keenness for human comradeship — 

 she is accordingly described as less intelligent than the male. 

 And yet her whole conduct is planned so that pregnancy and 

 motherhood may be successful. She knows the right amount 

 of exercise at each stage ; she knows at the critical time what she 

 herself has to do and what she expects you to do, and, if you go 

 beyond that, the hand will be held firmly in her mouth, to he 

 really punished if the intrusion be persistent. As a mother her 

 conduct is at every point pre-eminently intelligent ; the male is 

 only intelligent under circumstances wholly artificial. I have 

 digressed thus to indicate how on the mental side there is no 

 comparison between the value of the data at the disposal of the 

 experimental breeder and of the medical officer of health working 

 in conjunction with the school medical officer. The wages, the 

 habits, the employment of parents, the nature of the home, are 

 all at the service of the medical officer of health ; they have been 

 tabled in thousands and thousands of cases ; the physicjue and 

 mentality of thousands of children are studied Cvery day l)y 

 teacher and school medical officer. 



^Vhat is done with all this material ? What can be done 

 with it? I venture to assert that but little has been done with 

 it, and that but little can be done with it as circumstances are 

 at present. Let me give some of my reasons for these statements. 

 Jn the first place you have government officials and regula- 

 tions checking all useful inquiry into the actual health of the 

 children. You have an enormous number of children, and 

 in order for some inexplicable reason to cope with them all, 

 instead of studying selected samples, the school medical officer 

 is compelled to examine " entrants " and " leavers," and to do 

 this at a rate which destroys all efficiency in the examina- 

 tion. How can you find out anything useful in a five minutes" 

 examination ? Why, a really effective test of the eyesight woukl 

 occupy a quarter to half an hour ! And take that very cjuestion 

 of eyesight, what is it that we want to learn ? ^^'hy, we want to 



