THE USE OF THE LABORATORY 



15 



time in rediscovering the hundreds of thousands of facts already 



known about plants and animals, we would not get very far with 



any new discoveries. So we 



rely on texts and reference 



books because they have been 



written by specialists, and in 



this way we may make an 



earlier start toward discoveries 



of our own. 



Biology, more than any sub- 

 ject you are now studying, 

 ought to prepare you to think 

 logically. The method of the 

 experiment is much like the 

 steps of an act of real thinking. 

 In our attempt to solve a prob- 

 lem through an experiment we 

 use four steps : first, we state 

 our problem ; second, we do 

 certain things to try to find out 

 something about it ; third, we observe and analyze what we have 

 done ; and fourth, we draw a conclusion as the result of what we 

 have seen. These are the steps taken by any one who really 

 accomplishes anything in the way of constructive work. But in 

 an experiment, if we really want to prove our point, it is necessary 

 to establish a control. For example, suppose we want to know 

 what effect exercise has on the rate of our heart beat. We can 

 first take the pulse rate when quietly sitting at our desk or when 

 lying down, and then we can take a definite amount of exercise 

 and again take the pulse rate. In this way we establish a contrast 

 between the heart beat when we are at rest and when we have had 

 exercise. The rate of the pulse when we are at rest is known as 

 the control. Which of the two rates of the pulse just obtained 

 would be of real value in giving us correct information about our 

 normal heart beat? Experiments and projects with the proper 

 controls will give us the techniques we need to be thinkers and 

 doers in this world. 



John Hunter, a physiologist and surgeon, car- 

 ried on much biological research. He always 

 sought the truth through observations and ex- 

 periments on lower animals. 



