270 NATURAL SCIENCE. April, 



length they would be distinguished as two. Now, if this is really the 

 principle on which characters are to be defined, it is superfluous to 

 ask whence the independence in variations. That independence rests 

 on ignorance of causes, and is restricted, step by step, with the 

 growth of physiology. Were all the relations of function of the parts 

 of an organism known, it is simply inconceivable that the quantity or 

 quality of any part you like could be regarded as without effect on 

 the rest, or as having come to the condition in question without the 

 co-operation of the rest. And even if such a hiatus in the relations 

 of parts were thinkable, we have ample evidence that it does not 

 occur, in the cases of obscure correlation of phenomena of various 

 kinds in various parts apparently unconnected with one another in 

 any special manner. In every living thing the islands of connected 

 changes which rise here and there above our sea of ignorance are 

 united on a common bed, perhaps not so deep down as is usually 

 taken for granted. 



This false isolation of characters in the adult, and with regard to 

 inheritance and variation, is the chief cause of the assumption of 

 demon particles ; and in this connection it may be said that in the 

 expression latent characters, which are carried through one generation 

 or sex to appear in another, whether in cases of dimorphism, poly- 

 morphism, or atavism, we have a metaphor that often causes error, 

 though it would be pedantic to object to the convenient phrase. The 

 character simply does not exist in the intermediate generation, and 

 no carriers need be invented for it. To say that an appearance is 

 latent is to say that it is not. Though there were waves yesterday 

 and will be waves to-morrow, we do not think of saying when the sea 

 is calm that they are now^latent in the sea ; we simply say that there 

 are no waves, though we know that when the conditions arise they 

 will appear. A character is simply the appearance caused by the 

 reactions of circumstance and the mass of cells derived from the 

 germ, and in the absence of certain conditions certain characters 

 do not appear. This has been well shown in respect to one class of 

 characters by the valuable essay of Geddes and Thomson. The action 

 of circumstance must come into our account of the rise of alternative 

 structures and functions somewhere ; it is surely more reasonable to 

 regard it as directly answerable for the changes in question, and not 

 simply indirectly as awakening the demon carriers of one set of 

 structures which thereafter supersede the demons of the alternative 

 set which now become latent. For thus we have the support of 

 experiment, and substitute a physiological account for what is at best 

 only a bad formal one. One might as well say that men have within 

 them the carriers or determinants of a latent black eye, which are 

 called into action by a blow, as that the difference in form and function 

 of the sexes is due to the action of alternative sets of " determinant 

 vehicles of hereditary characters " one of which triumphs over the 

 other. If one alternative form differs from the other in one respect. 



