20 



Introduction 



systems and are known as the physical sciences. In contrast, the 

 sciences which deal with living systems are known as the biological 

 sciences. 



Actually this division is not so definite as it first seems, for many 

 of the functionings of living things can be explained only in the terms 

 of physics and chemistry. For this study, special fields have been 

 developed. Thus biophysics and biochemistry are now well-recognized 

 subjects that bridge the gap between the physical and biological sciences. 



500 



400 



EXPERIMENTAL ANIMAL i-« — «- 

 CONTROL ANIMAL o o- o 



300 



MGX 

 BLOOD 

 SUGAR 



200 



OPERATION 

 PERFORMED 



100 



Fig. 1. — Graph of experiment performed to illustrate the scientific method. In 

 order to study the role of the pancreas in maintaining the blood sugar level, the 

 pancreas was removed from one rat and the sugar content of the blood was an- 

 alyzed every twelve hours. Another animal, the control, was treated in exactly 

 the same manner as the experimental animal except that its pancreas was not 

 removed. In order for the control to be effective, litter mates of a known strain 

 of rats were used. Both animals were analyzed for blood sugar for two days before 

 the operations were performed. At this time, operations were performed on both 

 the experimental and control animals, but the pancreas was removed only from the 

 experimental animal. 



In biology itself, there are two fields which are truly distinctive only 

 at the higher levels. These fields are zoology dealing with animals, 

 and botany dealing with plants. Within each field, it has been neces- 

 sary to make many subdivisions because of the great complexity and 

 variety of organisms. Again these divisions are simply a matter of 



