PREFACE 



ELABORATE apparatus plays an important part in the science 

 of to-day, but I sometimes wonder if we are not inclined to 

 forget that the most important instrument in research must always 

 be the mind of man. It is true that much time and effort is devoted 

 to training and equipping the scientist's mind, but little attention 

 is paid to the technicalities of making the best use of it. There 

 is no satisfactory book which systematises the knowledge available 

 on the practice and mental skills — the art — of scientific investiga- 

 tion. This lack has prompted me to write a book to serve as an 

 introduction to research. My small contribution to the literature 

 of a complex and difficult topic is meant in the first place for the 

 student about to engage in research, but I hope that it may also 

 interest a wider audience. Since my own experience of research 

 has been acquired in the study of infectious diseases, I have 

 written primarily for the student of that field. But nearly all the 

 book is equally applicable to any other branch of experimental 

 biology and much of it to any branch of science. 



I have endeavoured to analyse the methods by which dis- 

 coveries have been made and to synthesise some generalisations 

 from the views of successful scientists, and also to include certain 

 other information that may be of use and interest to the young 

 scientist. In order to work this material into a concise, easily 

 understandable treatise, I have adopted in some places a frankly 

 didaciic attitude and I may have over-simplified some of the 

 issues. Nothing, however, could be further from my intentions 

 than to be dogmatic. I have tried to deduce and state simply as 

 many guiding principles of research as possible, so that the student 

 may have some specific opinions laid before him. The reader is 

 not urged to accept my views, but rather to look upon them as 

 suggestions for his consideration. 



Research is one of those highly complex and subtle activities 

 that usually remain quite unformulated in the minds of those who 

 practise them. This is probably why most scientists think that it is 



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