45 



Practical Plant Physiology 



An address by Mr. F. H, Bolster of the Gardena (California) 

 high school is quoted by Dr. Babcock in an article* on agri- 

 culture in the secondary schools ; part of the abstract of Mr. 

 Bolster's address is so eminently adapted to any high school and 

 shows so concretely the kind of work necessary for good botani- 

 cal teaching in any school that the following illustration is given. 



"The aims of the course were to give a little general knowledge 

 of several sciences to show how all these sciences are related to 

 agriculture, and last and most important, to develop the individual 

 by teaching him to reason. 



"We used no text but performed experiments which had a 

 direct bearing on agriculture. We would state the experiment 

 as a question and then try to answer the question. For example, 

 How deep should seed be planted? When seeds germinate, what 

 gas is given off? How may we best retain moisture in soils ? 

 How can we control alkali ? Do vetches grow better if inocu- 

 lated with bacteria, or if not inoculated? The material would be 

 placed before the pupils. The method would be described and 

 the precautions given. Then they would go about it and from 

 the result draw their conclusion which was the answer to the 

 question. But that was not enough. Take for instance an ex- 

 periment whose relation to agriculture is least obvious. What 

 gas is given off by germinating seeds ? They came to the con- 

 clusion that carbon dioxide was given off But what difference 

 does it make whether this gas is given off or not ? What bear- 

 ing does that have on agriculture ? If the experiment is left 

 there, we have only learned an interesting fact which is of no use 

 whatever. The experiment must be applied if it is to be made 

 valuable. I try to draw from the pupil the application to agri- 

 culture by reasoning from one step on to another. What is car- 

 bon dioxide ? A gas composed of carbon and oxygen. If car- 

 bon dioxide is given off by germinating seeds, what must be going 

 on in the seed? Oxidation or burning, the same as in our bodies 

 when we exhale the same gas, or when wood burns. Where 

 does the carbon come from ? From the seed itself. Where does 



* Nature Study Review. November, 1909. 



