354 



SCIENCE 



[Vol. LVI, No. 1448 



rational but instinctive, wiiereas at the height 

 of its vertebrate development reason is there 

 as well as instinct. Yet in both one outcome 

 seems to be the welding of individuals into 

 societies on a scale of organization otherwise 

 unattained. The greatest social animal is man 

 and the powers that make him so are mental; 

 language, tradition, instinct for the preserva- 

 tion of the community, as well as for the pre- 

 servation of the individual, reason actuated by 

 emotion and sentiment, and controlling and 

 welding egoistic and altruistic instincts into 

 one broadly harmonious, instinctive-rational be- 

 havior. Just as the organization of the cell- 

 colony into an animal individual receives its 

 highest contribution from the nervous system, 

 so the further combining of animal individuals 

 inito a multi-individual organism, a social com- 

 munity, merging the interests of the individual 

 in the interests of the group, is due to the 

 nervous system's crowning attributes, the 

 mental. That this integration is still in pro- 

 cess, still developing, is obvious from the whole 

 course of human pre-history and history. The 

 biological study of it is essentially psycho- 

 logical; it is the scope and ambit of social 

 psychology. Not the least interesting and im- 

 portant form of social psychology is that rela- 

 tively new one, dealing with the stresses and 

 demands that organized industry makes upon 

 the individual as a unit in the community of 

 our day and with the readjustments it asks 

 from that community. 



To resume, then, we may, I think, conclude 

 that in some of its aspects animal life presents 

 ,to us mechanism the "how" of which, despite 

 many gaps in our knowledge, is fairly ex- 

 plicable. Of not a few of the processes of the 

 living body, such as muscular contraction, the 

 circulation of the blood, the respiratory intake 

 and output by the lungs, the nervous impulse 

 and its journeyings, we may fairly feel, from 

 what we know of them already, that further 

 application of physics and chemistry wiU fur- 

 nish a competent key. We may suppose that 

 in the same sense as we can claim to-day that 

 the principles of a gas-engine or an electro- 

 motor are comi^rehensible, so will the bodiiy 

 working in such mechanisms be understood by 



us, and indeed are largely so already. It may 

 well be possible to understand the principle 

 of a mechanism which we have not the means 

 or skill ourselves to construct; for example, we 

 cannot construct the atoms of a gas-engine. 



Turning to other aspects of animal meehau'- 

 ism, such as the shaping of the animal body, 

 the conspiring of its structural units to com- 

 pass later functional ends, the predetei-mina- 

 tion of specific growth from egg to adult, the 

 predetermined natural term of existence, these 

 and their intimate mechanism, we are, it seems 

 to me, despite many brilliant inquiries and in- 

 quirers, still at a loss to understand. The steps 

 of the results are known, but the springs of 

 action still lie hidden. Then again, the "how" 

 of the mind's connexion with its bodily place 

 seems still utterly enigma. Similarity or iden- 

 tity in time-relations and in certain other ways 

 between mental and nervous processes does not 

 enlighten us as to the actual nature of the 

 connexion existing between the two. Advance 

 in biological science does but serve to stress 

 further the strictness of the nexus between 

 them. 



Great differences of difficulty therefore con- 

 front our understanding of various aspects of 

 animal life. Tet the living creature is funda- 

 mentally a unity. In trying to make the "how" 

 of an animal existence intelligible to our im- 

 perfect knowledge we have, for purposes of 

 study, to separate its whole into part-aspects 

 and part-mechanisms, but that separation is 

 artificial. It is as a whole, a single entity, that 

 the animal, or for that matter the plant, has 

 finally and essentially to be envisaged. We 

 cannot really understand one part without the 

 other. Can we suppose a unified entity which 

 is part mechanism and part not? One privilege 

 open to the human intellect is to attempt to 

 comprehend, not leaving out of account any 

 of its properties, the "how" of the living 

 creature as a whole. The problem is ambi- 

 tious, but its importance and its reward are 

 all the greater if we seize and attempt the full 

 width of its scope. In the biological synthesis 

 of the individual it is concerned with mind. It 

 includes examination of man himself as acting 

 under a biological trend and process which is 



