1096 LIFE : OUTLINES OF GENERAL BIOLOGY 



"nurture", (c) It is rightly said that an evolution theory, dealing 

 with the ascent of life, is unthinkable if it takes no account of the 

 individual's experience and changing endeavour. But the role of 

 the individual is to play its hereditary hand of cards, to put its 

 mutations and fluctuations to the test in the struggle for existence —  

 a test which determines survival. A change in the intensity of en- 

 deavour may readily arise as a germinal variation — by hypothesis 

 heritable, (d) In cases where particular species are known only from 

 uniform surroundings, all the members with similar diet and habits, 

 it is quite possible that some of the constant specific characters, on 

 which the systematist relies, are modificational. They re-appear 

 uniformly because they are re-impressed on each successive crop. 

 Experiments are urgently required in this connection, [e] No biologist 

 has any doubt as to the importance of modifications for the individual, 

 or as to the general plus or minus effect that some of them may have 

 on the vigour of the stock. 



10. Novelties or new departures in organisms may be classified 

 as follows: 



A. Somatic Modifications. 



Degree of transmissibiUty uncertain. 



B. Germinal Variations. 



(i) Mutations, arising abruptly, very heritable, mendel- 



ising. 

 (2) Fluctuations, quantitative, with intergrades, often 



heritable, tending to blend. 



From these some would separate off germinal variations induced 

 by nurtural peculiarities (e.g. changes in terrestrial radiation!) 

 which influence the germ-cells through the body, or through modifica- 

 tions effected in the body but evoking other changes in the offspring. 

 As stated already, one of the authors of the present volume holds 

 by the view that an organism need not cease to originate novelties 

 after it passes beyond the one-cell phase of its being. A flowering 

 plant may become more floral, and another may vary in the direction 

 of grassiness; in one type the axis may be shortened down, while in 

 another it is lengthened out; one animal may tighten its bow of 

 endeavour and another relax it ; one type may prolong its embryonic 

 phase and another its larval period. Such organismal or constitutional 

 variations, based on deeply rooted, old-estabhshed alternatives, e.g. 

 of metabolism and development, may somehow repercuss on the 

 germ-cells and thus affect the succeeding generations. This is a 

 subtle Neo-Lamarckism. 



11. Wherever there is among animals, e.g. in ant-hill or bee-hive, 

 something of the nature of a social heritage, or permanent products, 

 or a tradition, or a lasting change of the environment, or an external 

 system of inter-relations, then variations will be subtly tested 



