84 PART II. SOME IMPORTANT METHODOLOGICAL TERMS. 



and agitated through our moving, breathing, and speaking ; dif- 

 fusion of bodily warmth; and the like circumstances. These 

 are, in any case, not deliberately produced transformations, and 

 are generally not impossible to guard against when we are 

 aware of them. 1 



Direct experiments cannot be resorted to in all forms of en- 

 quiry, as, for example, in astronomy or generally in geology. 

 Nor are they everywhere equally profitable. In the biological 

 sciences, where not only the same object differs materially at 

 different times and differs conspicuously from nearly related 

 objects the protein of no two species appears to be identical 

 in composition, but where interrelations and interactions of a 

 most complicated order. obtain, as illustrated, for instance, by 

 the cerebro-spinal system in man, experiment is at a decided 

 disadvantage, and its results are frequently found to be of 

 questionable value. On the other hand, where, as in mechanics 

 and chemistry, the material investigated is, relatively to life 

 forms, homogeneous in character, experiment achieves its most 

 signal triumphs. For the same reason, experiment becomes 

 progressively more profitable as the material investigated is 

 simplified through accumulated discoveries, whereas its value 

 diminishes in proportion as the amorphous mass of primitive 

 fact and fancy is unsifted. These limitations to experimental 

 enquiries should warn the methodologist against presuming that 

 experiment can be applied ubiquitously, and that it is in all 

 circumstances alike of telling benefit; and, more than this, a 

 survey of the sciences should convince him that an extensive 

 domain exists at present where observation, with or without 

 instruments, is resorted to on a comprehensive scale and with 

 eminently gratifying results. Indeed, in many directions as 

 in map and chart construction the information required is 

 derived, solely almost, from exhaustive observation and mea- 

 surement. 



Bacon had a just conception of experiment, and incessantly 

 had recourse thereto. What could be more complimentary to 

 those who believe in addressing pointed questions to nature 

 than this? "The subtlety of experiments is far greater than that 

 of the sense itself, even when assisted by exquisite instruments ; 

 such experiments, I mean, as are skilfully and artificially 

 devised for the express purpose of determining the point in 



1 Venn, in his Logic, pp. 416-417, says on this subject: "Our bodies are 

 heavy, and, therefore, the mere approach to the machine has altered the 

 magnitude and direction of the resultant attraction upon the scales. Our 

 bodies are presumably warmer than the surrounding air; accordingly we 

 warm and therefore lighten the air in which the scales hang, and if the 

 two scales and their contents are not of the same volume we at once alter 

 their weight as measured in the air. Our breath produces disturbing currents 

 of air. Our approach affects the surface of the non-rigid floor or ground on 

 which the scales stand, and produces another source of disturbance, and so 

 on through the whole range of the physical forces." 



