RESEARCH IN BIOLOGY 13 



since man could never have become civilized without being aware of 

 the world of living things. Biology has been scientific in the usual 

 sense, however, for only a few centuries. For a number of reasons biology 

 has always developed only after developments in the physical sciences. 



The earliest scientific biologists were descriptive scientists, concerned 

 with naming and describing organisms. The invention of the microscope 

 permitted the examination of smaller units, but the approach of the 

 biologists remained about the same; that is, they still described what they 

 saw. In time, it became possible to consider more abstract relationships. 

 Changes that take place over a period of time, as in the growth of an 

 animal or plant, or as in the various physiological processes within an 

 individual, obviously require a rather different kind of observation. If 

 a biologist is to explain the interrelationships of the activities of various 

 organs in an animal, a higher level of intellectual activity is required than 

 if he merely describes their structure. 



The experimental approach is especially valuable in these highly ab- 

 stract phases of biology. In fact, about 1625 William Harvey used some 

 of the first experiments in biology to demonstrate the continuous circula- 

 tion of the blood. At about the same time, van Helmont's experiment 

 showed that plants do not take all their food from the soil. About a cen- 

 tury later Stephen Hales performed many experiments on the pressures 

 and the movement of liquids within plants and animals. His books, 

 Vegetable Staticks (1727) and Haemastaticks (1732), demonstrate the 

 ingenuity of the man, as well as providing very interesting reading. 

 Physicists at the time were measuring pressure by observing the height 

 to which a liquid would rise in a tube. Hales applied similar observa- 

 tions in biology. In one heroic experiment he measured the blood pres- 

 sure of a horse by attaching a long glass tube to one of the large arteries 

 in the horse's neck. Fortunately this method of measuring blood pressure 

 never became popular among the physicians. It is enlightening to read 

 a modern laboratory manual for plant physiology, to compare it with 

 Vegetable Staticks, and to note how many of the usual experiments in 

 present-day courses were actually designed by Stephen Hales. 



One of the major philosophical battles in the field of biology was 

 the mechanist-vitalist controversy about the end of the nineteenth cen- 

 tury. The mechanists maintain that there is nothing about the living 

 organism that cannot be explained in terms of physics, chemistry, and 

 mathematics. According to the vitalists, there was some vital force, some 

 living being, above and beyond the physical laws. Progress in the 

 biological sciences has depended on the assumption of the mechanistic 



