METHOD IN SCIENCE 19 



disease, with nutriment itself, or with excretions. It seems, 

 then, that in birth, life, disease, and death itself, what we 

 witness is the use, acquisition, or failure and gradual loss of 

 " acquirements." 



When we consider that in all inductive arguments what- 

 ever we can only attain a high degree of probability, a 

 proposition put very clearly by Jevons, it assuredly seems 

 that catalysts can be acquired, as they can even more 

 certainly be lost. Such a theory is not only of value in 

 biology and the ordinary course of practical medicine, but 

 may probably be employed with advantage in the study of 

 the. origins of disease lately commenced at St. Andrews by 

 Mackenzie. His research will undoubtedly deal with the 

 future effect on the youthful organism of the passing ail- 

 ments of children, the lasting results of early innutrition 

 or want of food factors, and into the probability of such 

 disorders as periodontitis having early undiscovered 

 stages which affect the whole metabolic or catabolic 

 machinery of the patient. It should not be forgotten that 

 studies of this kind were suggested by Galton. If con- 

 sidered analogical reasoning should thus tend to support 

 the intuition and clinical knowledge of the physician it 

 cannot be disdained. It is obvious, and should need no 

 proof, that the imagination, controlled by knowledge, is an 

 integral part of the logic of discovery. It is the Mount 

 Pisgah of science. 



Since I hope to have shown with some plausibility that 

 such obscure phenomena as mitosis and the vexed question 

 of transmission of acquired and altered characteristics can 

 be illustrated, and made clearer by the examples just given, 

 and since such considerations threw light on the nature of 

 a cell-nucleus, and enabled us to think of it as a store-house, 

 while we look on catalysts as tools picked up on the 



