740 



SCIENCE. 



[N. S. Vol.. IV. No. 99. 



8. Let us suppose, however, that a group 

 of organisms belonging to a plastic species 

 is placed under new conditions of environ- 

 ment. 



9. Those whose innate somatic plasticity 

 is equal to the occasion survive. They are 

 modified. Those whose innate plasticity is 

 not equal to the occasion are eliminated. 



10. Such modification takes place gen- 

 eration after generation, but, as such, is not 

 inherited. There is no transmission of the 

 effects of modification to the germinal sub- 

 stance. 



11. But variations in the same direction 

 as the somatic modification are now no 

 longer repressed and are allowed full scope. 



12. Any congenital variations antago- 

 nistic in direction to these modifications 

 will tend to thwart them and to render the 

 organism in which they occur liable to 

 elimination. 



13. Any congenital variations similar in 

 direction to these modifications will tend to 

 support them and to favor the individuals 

 in which they occur. 



14. Thus will arise a congenital predis- 

 position to the modifications in question. 



15. The longer this process continues, 

 the more marked will be the predisposition 

 and the greater the tendency of the con- 

 genital variations to conform in all respects 

 to the persistent plastic modifications; while 



16. The plasticity continuing the opera- 

 tion, the modifications become yet further 

 adaptive. 



17. Thus plastic modification leads and 

 germinal variation follows; the one paves 

 the way for the other. 



18. Natural selection will tend to foster 

 variability in given advantageous lines 

 when once initiated, for (a) the constant 

 elimination of variations leads to the sur- 

 vival of the relatively invariable ; but (6) 

 the perpetuation of variations in any given 

 direction leads to the survival of the vari- 

 able in that direction. Lamarckian pale- 



ontologists are apt to overlook this fact 

 that natural selection produces determinate 

 variation. 



19. The transmissionist, fixing his atten- 

 tion first on the modification, and secondly 

 the fact that organic effects similar to those 

 produced by the modification gradually be- 

 come congenitally stereotyped, assumes that 

 the modification as such is inherited. 



20. It is here suggested that the modifi- 

 cation as such is not inherited, but is the 

 condition under which congenital variations 

 are favored and given time to get a hold 

 on the organism, and are thus enabled by 

 degrees to reach the fully adaptive level. 



When we remember that plastic modifi- 

 cation and germinal variation have been 

 working together all along the line of 

 organic evolution, to reach the common goal 

 of adaptation, it is difficult to believe that 

 they have been all along wholly independ- 

 ent of each other. If the direct dependence 

 advocated by the transmissionists be re- 

 jected, perhaps the indirect dependence 

 here suggested may be found worthy of 

 consideration. 



C. Lloyd Mokgan. 



Univeesity College, 



Beistol, England. 



NATURE STUDY AND INTELLECTUAL 

 CULTURE. * 



It is impossible to dissociate the intel- 

 lectual effect of ' nature study ' from the 

 other factors in training which habitually 

 accompany it. So far as I know, no * pure 

 culture ' to determine the specific effect of 

 nature study has ever been attempted ; so 

 that the best that can be done is in the way 

 of reasonable inference. There can be no 

 doubt that much of its effect is cumulative 

 rather than specific, and so becomes merged 

 and lost among other agencies. In addi- 

 tion to this general result, however, it is 



* Prepared for presentation before the Department 

 of Natural Science Teaching, N. E. A., BufEalo, 1896. 



