bigelow] NATURE-STUDY IN HIGH SCHOOLS 77 



because you have killed all that were present in the can and 

 bread originally and prevented any more from entering. 



Experiment 3. To see whether germs abound in the air. Open 

 the can used in Experiment 2, thus allowing the air to enter. Let 

 the cover remain oft" for a day or so and observe whether the 

 bread then molds or not. Do not allow it to become dry, since 

 molds can not grow in dry substances at all. 



Germs are drifting about in the air in very great abundance, 

 and when the can is open many of them will fall upon the bread 

 and begin to grow. The fact that they do develop thus shows that 

 the air contained them in considerable quantity. 



Whenever you see apples or other fruit decaying it is because 

 germs somewhat similar to those of the bread have gotten under 

 the skin of the fruit and are there growing, thus causing the decay. 

 If the entrance of these germs could be prevented, the fruit 

 would not decay. On the other hand, if germs are placed in 

 healthy apples, decay is produced. You may illustrate by an 

 experiment. 



Experiment 4. Secure a perfectly healthy apple and a rotten 

 apple in a well developed condition of rot, that is, an apple cov- 

 ered with mold. Stick a hat-pin into the mold and then into the 

 healthy apple. Set the healthy apple away and watch it from day 

 to day to see whether the rot develops in the place where you 

 planted the mold. 



Another disease on the sweet potato which causes the potato 

 to become soft and mushy is a good disease to use in a similar 

 experiment, to illustrate the same point. 



From all of the above experiments the child will glean a number 

 of valuable facts and insight and interest in a feature of daily life 

 with which very few people are in touch. 



NATURE-STUDY IN HIGH SCHOOLS 



BY MAURICE A. BIGELOW 

 Teachers College, Columbia University 



The explanation on the cover that The Xature-Study Review 

 is a journal " devoted to all phases of nature-study for elementary 

 schools " has led readers to inquire why nature-study is thus em- 

 phasized as an elementary-school subject when much work in the 



