158 ON THE INTERNAL FORM AND [ch. 



idioplasts, ids, or other constituent particles of protoplasm or of 

 the cell, we are apt to fall into the error of attributing to matter 

 what is due to energy and is manifested in force : or, more strictly 

 speaking, of attributing to material particles individually what is 

 due to the energy of their collocation. 



The tendency is a very natural one, as knowledge of structure 

 increases, to ascribe particular virtues to the material structures 

 themselves, and the error is one into which the disciple is likely 

 to fall, but of which we need not suspect the master-mind. The 

 dynamical aspect of the case was in all probability kept well in 

 view by those who, like Goodsir himself, first attacked the problem 

 of the cell and originated our conceptions of its nature and 

 functions. 



But if we speak, as Weismann and others speak, of an 

 "hereditary substance/'' a substance which is split off from the 

 parent-body, and which hands on to the new generation the 

 characteristics of the old, we can only justify our mode of speech 

 by the assumption that that particular portion of matter is the 

 essential vehicle of a particular charge or distribution of energy, 

 in which is involved the capability of producing motion, or of 

 doing "work." 



For, as Newton said, to tell us that a thing "is endowed with 

 an occult specific quality, by which it acts and produces manifest 

 effects, is to tell us nothing; but to derive two or three general 

 principles of motion* from phenomena would be a very great step 

 in philosophy, though the causes of these principles were not yet 

 discovered." The things which we see in the cell are less important 

 than the actions which we recognise in the cell; and these latter 

 we must especially scrutinize, in the hope of discovering how far 

 they may be attributed to the simple and well-known physical 

 forces, and how far they be relevant or irrelevant to the phenomena 

 which we associate with, and deem essential to, the manifestation 

 of life. It may be that in this way we shall in time draw nigh to 

 the recognition of a specific and ultimate residuum. 



* This is the old philosophic axiom writ large: Ignorato motu, ignoratur 

 natura ; which again is but an adaptation of Aristotle's phrase, 17 dpxv rrjs Kivr]<T€us. 

 as equivalent to the "Efficient Cause." FitzGerald holds that ''all explanation 

 consists in a desciiption of underlying motions"; Scientific Writings, 1902, p. 385. 



