484 DISCUSSION 



Let us take possible objections first. Vivisection, however important in 

 the academic teaching of physiology, need play no part in a course such as 

 I visualise. Secondly, will the pupils develop a morbid awareness of the 

 workings of their own bodies ? I do not think so. Knowledge of the 

 normal should do no one any harm. The medical student develops his 

 hypochondriacal ills only after he starts the study of pathology, medicine 

 and surgery. 



However, teaching of human physiology to what one may call a lay 

 audience does demand care. A school teacher fussily insistent on the 

 importance of daily evacuation of the bowels may create an impossible 

 situation. But that is a risk which should be run. I believe that proper 

 school instruction in nutrition and dietetics, with, of course, practice of 

 what was taught, would halve our national bill for purgatives within a few 

 years. 



Now for the biological first principles. The human body is ideal for 

 the teaching of facts about growth, movement, alimentation, respiration, 

 circulation. But I have doubts about reproduction and excretion. I know 

 it is all wrong, but it cannot be helped. I am afraid of the earnest self- 

 conscious teacher and the uncomfortable self-conscious pupil if these two 

 principles are tackled by direct reference to man. It can be done, as I have 

 done it, through the comparatively impersonal medium of broadcasting, 



but . So these two first principles of excretion and of reproduction are 



best tackled by reference to lower forms of life. In the future we may be 

 more sensible. 



Now the last problem of practical work, and it is relatively simple. There 

 is no need for elaborate apparatus. 



May I give one or two examples of the type of practical work which 

 succeeds in broadcast courses and in adult education work where the 

 pupils, although grown-up, are receiving instruction in biological science 

 for the first time. 



Let us take the practical work in a, shall we say, ' physiological ' order. 



Alimentation, food and digestion : 



An institution teaching chemistry can make quite a feature in practice of 

 the simpler test-tube reactions characteristic of the proximate principles of 

 food, and the action of saliva on starch serves very well as an example of 

 enzyme action. After that, digestion in the amoeba becomes less of a 

 text-book myth. 



Using any of the standard food tables, analysis of weighed portions of the 

 commoner domestic food-stuflFs, of fruits and of vegetables, in terms of water, 

 proximate principles, and of vitamins, makes quite an instructive exercise. 



Circulation : 



I see no reason why palpation of the pulse, even listening to the heart 

 with a stethoscope, should not be used in teaching the facts of the circulation 

 to quite young people. Older pupils can be asked to graph the effect of 

 exercise on the pulse, and to observe the eflFect of skin temperature on skin 

 colour. But I should omit blood pressure observations — partly, since a 

 sphygmomanometer costs money, and partly, since the general public is far 

 too blood pressure-conscious already. And examination of a drop of human 

 blood has a vividness and reality quite absent from contemplation of a jar 

 of ox blood from the slaughter-house or blood from a dismembered frog. 

 Stained human leucocytes are more real than the story of Metchnikoff and 

 his phagocytes. 



