EXPEHIMENTS IN TEACHING ISOTANV. 577 



an experiment." Everybody knows that the candidates do not 

 devise experiments : not even the teachers do, as a rule. Such 

 questions imply a false standard : they encourage what Socrates 

 called a pretence of knowledge without the reality, i hus it is 

 that we fiave run our idea to death, and have been ourselves 

 caught by a catch-word. 



I am not, of course, advocating the abolition of all experi- 

 ment. A certain amount of it is spontaneous. Every baby puts 

 his finger into the fire at least once, just to see what will happen. 

 Every child pulls up the seeds he has planted to see if they are 

 growing. All gardening and farming operations are of the nature 

 of experiment. Often, indeed, in the germination of seeds Nature 

 is as quaint as we are in our laboratories : for instance, I have 

 seen a Loranthus seedling tr\'ing to extract nourishment from a 

 ■barbed-wire fence. And in such natural experiments, eking out 

 Nature's activities with our own, there is plenty of scope in ele- 

 mentary instruction without having recourse to abstruse chemical 

 tests or elaborte measurements of abnormal growths by auxano- 

 meters and things. 



Let me specify. In order to recognize the presence of sugar 

 in plants, I want t i re'.y on the test which 



Nature provides : namely, our sense of taste. The kind of answer 

 I want from them is somewhat as follows : " I know there is 

 sugar as well as acid in apricots and other ifruits, because I taste 

 both together : I know there is sugar in ripe grapes because they 

 are sweet ; 1 know there is sugar in sugar-cane and beet-root, 

 because sugar is actually made from them : I know there is sugar 

 in the nectar of flowers because I have tasted it in Kafir-honey- 

 suckle {Tecomaria capcnsis) and Sugar-bush {Protea mellifera). 

 I know there is sugar in carrots because you can sweeten pastry 

 by making it with water in which carrots have been boiled." But 

 this answer is too crude for our examiners : they want chemical 

 tests. The sort of answer by the same candidate now is: " You 

 apply to the specimen some chemical stuft' which I know nothing 

 about : it makes some difference or other which I cannot remem- 

 ber, in a plant whose name I have forgotten because I had no 

 interest in the experiment : and chemists say that proves the pre- 

 sence of sugar — which I know already by the taste." So al?^3 

 with lignin. It is quite easy, even with a simple microscope, and 

 even without staining, to demonstrate all the candidate needs to 

 know about the nature of wood in both structure and function ; 

 but again this direct observation is discouraged. It is blind faith 

 the examiners want, not knowledge. So I go to my pupils and 

 say. " You must take the chemist's word for it that this stuff is 

 not powdered sugar or alum but phlorogkicin, whatever that is. 

 When it touches wood, it strikes it pink, and you must again take 

 the chemist's word that there is nothing else it will turn pink." 

 So we try the " experiment." and the pink comes. *' What does 

 that Drove?" thev a«k. "It proves that this is wood." "But 

 we knew it was wood" " Tust so: and we can now tell the 

 chemist that wood is a splendid test for phlorogkicin ; but you 



