xxviii Presidential Address 



methods as the observation of animals in their natural habitats, the dis- 

 section of animals, the study of their embryology, and the examination of 

 the histological characters of animal tissues ; whereas in chemistry research 

 consists largely of the preparation of new compounds, the determination of 

 their composition, physical constants, and other properties, and the study 

 of the nature of the changes which occur when substances are brought into 

 contact under different physical conditions. When sufficient facts have 

 been collected it becomes possible for some generalization to take place, 

 the accuracy of which can be tested by further experiments suggested bv 

 the generalization. This generalization we call a " theory " or " hypothesis," 

 and if all deductions based upon the hypothesis are found to be in accord- 

 ance with fact the theory is accepted as a general guide for future work 

 until facts are discovered which force upon us the rejection or modification 

 of the theory. A theory is thus to the scientific experimenter what a map 

 is to the explorer. If the map is wrongly drawn the explorer will soon find 

 himself in difficulties. If the errors are only small the map will be of use 

 as a sketch-map, but the explorer will learn not to rely upon it for points 

 of detail. So also an hypothesis, which is the incomplete expression of a 

 sound principle, may be of considerable use, in that it will indicate much 

 which would not be foreseen without it. Eventually, however, it will be 

 found wanting, since it is not a strictly true representation, but only 

 allows us to " see as through a glass, darkly." Again, just as a correct 

 map may be misinterpreted, so also a strictly accurate hypothesis may 

 through unsound reasoning lead to deductions which are quite unwarranted. 

 Theories, then, are of great practical utility ; indeed, rapid practical develop- 

 ment usually follows each great advance in theoretical conception. 



It is obvious that research work may be undertaken cither from a desire 

 for knowledge itself or in order that the knowledge may be turned to some 

 economic use. Research undertaken with the latter object is commonly 

 spoken of as " technical research," and undoubtedly its prosecution is looked 

 upon by the public with far more sympathy than is the research based 

 upon a desire for knowledge alone. Whilst not deprecating in any way 

 the technical application of scientific knowledge, I believe that the view 

 of the public, that technical research is of more importance than research 

 carried out with the object of increasing our knowledge of the laws of 

 nature, is fundamentally wrong, for it cannot be too strongly emphasized 

 that in every science the greatest advances which have been made, and 

 which have led ultimately to the most important technical developments, 

 have usually been those which were carried out by seekers after truth with 

 regard to the laws of nature, and not to those who expected commercial 

 returns from their investigations. On the other band, I would enter my 

 protest against the views of those who scoff at their fellow-workers when 

 attempting to apply scientific knowledge to commercial development and 

 to the benefiting of mankind. It has been my privilege to study under 

 some of the greatest scientific thinkers in Great Britain and on the Continent 

 of Europe, and I can say that, though most of these men devoted their 

 labours to the elucidation of nature's laws, they were ever ready to take 

 an interest in the application of their discoveries to useful ends, and to 

 encourage their students to accept positions in which scientific knowledge 

 could be applied to the solution of the problems of the factory and the 

 workshop. No greater example of this can be quoted than that of the 

 late Emil Fischer, whose death in 1919 caused sorrow in all scientific circles. 

 Though the first of the so-called aniline dyes was prepared by William 

 Henry Perkin in 1856, the real chemical nature of these substances 

 remained a mystery until Fischer unravelled the tangled skein in 1878, 



