294 CONCLUSION 



the organs principally affected ; because a change in one important 

 organ would necessitate other changes throughout the whole 

 organism, in order to establish a new balance of functions. Thus, 

 variations which may be induced for a time in higher oi-ganisms, 

 continually tend, when the modifying influences have disappeared, 

 to be dwarfed and perhaps ultimately abolished, owing to the sum 

 total of internal forces acting in such a manner as gradually to 

 reproduce the former condition of equilibrium. 



But how different are the phenomena when we turn our 

 attention to lower organisms. 



If the facts made known, and the views that I have been 

 advocating, seem difficult of acceptance to many, as to a reviewer 

 in "Nature" ' who said, in reference to some of the facts, that they 

 were "entirely beyond credence, because so meaningless," I would 

 say, let them keep steadily in mind all that has been adduced, as 

 matter of common knowledge, concerning the isomeric states of 

 various saline substances, their transformations in crystalline form, 

 in colour, and in other characters — under variations in external 

 conditions ; as well as the total transformations of such elemen- 

 tary substances as carbon, phosphorus and sulphur owing to 

 alterations in the exact collocation of the atoms in their component 

 molecules. Such phenomena may help to supply something as to 

 the meaning of heterogenetic transformations. 



These alleged facts concerning heterogenesis may also be said 

 to be inconceivable. Granted : but that is no reason for doubting 

 their validity. How far are the processes of allotropism and 

 isomerism themselves conceivable, in any true sense of the word ? 

 Our notions of conceivability in regard to physical phenomena have 

 received many severe shocks even during the last two years — by 

 revelations concerning wireless telegraphy, the " mystery of 

 radium," and the constitution of matter itself — that is, of the 

 " simple atoms " of which elementary substances are composed. 

 Thus, Sir Oliver Lodge tells us that we are now arriving at an 

 electrical theory of matter == ; that in an atom of hydrogen there are 

 nearly i,ooo electrons, and in the mercury atom 100,000 electrons. 

 But the electrons are so minute that even with these vast numbers 

 in a single atom, they do not " fill all the space, and if the distance 

 between them were calculated, they seemed to be about as far 



' Feb. 25, 1904, p. 386. 



" See " Nature," March 12, 1903. 



