EVOLUTION 1095 



6. Among the novelties which crop up among organisms, in some 

 plastic types more than others, e.g. among plants more than among 

 mobile animals, there are numerous somatic changes that can be 

 experimentally proved (too often only surmised) to be the direct 

 results of peculiarities in external conditions and mode of life. They 

 are directly impressed on the body of the individual as the results of 

 peculiarities in environment and nutrition, use and disuse; and they 

 have unfortunately received the name "acquired characters", mean- 

 ing that they are directly impressed on, or acquired by the body 

 of the individual. They are more usefully called "somatic modifica- 

 tions", and may be defined as changes directly impressed on the 

 individual body as the result of peculiarities in surroundings, food, 

 habits, and endeavours, and so transcending the limits of organic 

 elasticity that they persist even after the inducing conditions have 

 ceased to operate. 



7. It is generally admitted, e.g. by Weismann, that deep external 

 changes, e.g. of climate, may so saturate through the organism that 

 they influence the germ-ceUs as well as the body, and may thus have 

 an effect on subsequent generations, though not necessarily the same 

 effect as that expressed in the original modification. It is also 

 admitted that deep influences from without, e.g. poisoning or 

 starving, a tonic environment or generous nutrition, may in a general 

 way decrease or increase the vigour of the germ-cells, and thus of 

 the offspring. It is also admitted that outside influences may serve 

 as trigger-pulling, liberating stimuli which induce new germinal 

 variations. Moreover, a modification may serve as a- life-preserving 

 individual change for successive generations until, it may be, a 

 germinal variation in the same direction has opportunity to occur 

 and time to estabUsh itself. 



8. There seems to be as yet very little convincing evidence that 

 a somatic modification can be transmitted or continued on to the 

 next generation as such or in any representative degree; but it is 

 too soon to deny the possibiUty. The cases pointing towards admit- 

 ting the possibiHty have been illustrated in the text ; they are mostly 

 of a difiicult and unusual t3rpe. 



9. The whole question is very difficult — ^much more difficult than 

 is sometimes hurriedly supposed — and it is of great theoretical and 

 practical importance. A few misunderstandings may be referred 

 to. (a) There is little use in saying that every novel character must 

 have been acquired sometime, for the word "acquired" is here used 

 ambiguously. That a novelty may be established as a racial character 

 is obvious ; the question is whether this is ever true of novelties that 

 begin as extrinsic modifications, not as germinal variations, (b) It 

 is certain that most characters of hving creatures require an appro- 

 priate "nurture" if they are to develop aright; but the question at 

 issue concerns changes of body that are impressed by pecidiarities in 



