PREPARATION 



different writers, inconsistencies between some observed aspect 

 of the local problem and previous reports, analogies with related 

 problems, and for clues during his field observations. The active- 

 minded investigator usually finds plenty of scope for the formula- 

 tion of hypotheses to explain some of the information obtained. 

 From the hypotheses, certain consequences can usually be proved 

 or disproved by experiment, or by the collection of further 

 observational data. After thoroughly digesting the problem in 

 his mind, the investigator decides on an experiment which is 

 likely to give the most useful information and which is within 

 the limitations of his own technical capacity and the resources 

 at his disposal. Often it is advisable to start on several aspects 

 of the problem at the same time. However, efforts should not 

 be dispersed on too wide a front and as soon as one finds some- 

 thing significant it is best to concentrate on that aspect of the 

 work. 



As with most undertakings, the success of an experiment 

 depends largely on the care taken with preliminary preparations. 

 The most effective experimenters are usually those who give 

 much thought to the problem beforehand and resolve it into 

 crucial questions and then give much thought to designing experi- 

 ments to answer the questions. A crucial experiment is one which 

 gives a result consistent with one hypothesis and inconsistent with 

 another. Hans Zinsser writing of the great French bacteriologist, 

 Charles Nicolle, said : 



" Nicolle was one of those men who achieve their successes by 

 long preliminary thought before an experiment is formulated, 

 rather than by the frantic and often ill-conceived experimental 

 activities that keep lesser men in ant-like agitation. Indeed, I have 

 often thought of ants in observing the quantity output of ' what- 

 of-it ' literature from many laboratories. . . . Nicolle did relatively 

 few and simple experiments. But every time he did one, it was 

 the result of long hours of intellectual incubation during which 

 all possible variants had been considered and were allowed for 

 in the final tests. Then he went straight to the point, without 

 wasted motion. That was the method of Pasteur, as it has been 

 of all the really great men of our calling, whose simple, conclu- 

 sive experiments are a joy to those able to appreciate them."^°® 



Sir Joseph Barcroft, the great Cambridge physiologist, is said to 

 have had the knack of reducing a problem to its simplest elements 



II 



