August 6, 1920] 



SCIENCE 



117 



names as they occur to me — are still chasing 

 this will-o'-the-wisp; and moth-like I can not 

 but flutter after them. Of the nitrifying bac- 

 teria which assimilate inorganic matter, of the 

 synthetic amines of animal nutrition, of the 

 properties of colloids, I have spoken already 

 to-day and last year ; but " how," says Dr. Hal- 

 dane, " is constant form maintained amid the 

 continuous changes of our changing matter? " 

 and — I may add — of variations of parts. Is 

 " form " something after the manner of seal, 

 which is impressed upon matter? or is it, in 

 Aristotle's sense, a kind of soul (entelechy) 

 which shapes the potential, or capacity, into 

 integral being ? Here we hover between meta- 

 physical or ontological concepts and natural 

 law, or the properties of matter. A few years 

 ago all notion of self-shaping was dismissed, 

 and the animal regarded merely as a diagram 

 of incident forces; to-day there is some hark- 

 back, if not to moulding entities, at any rate to 

 some phases which partake both of germ and 

 matrix. We had been taught that for develop- 

 ment functional stimuli were all that was nec- 

 essary; for instance, that the heart grew, even 

 beyond the normal, only in response to demand 

 for its work and by increased supply of blood 

 to its tissues. But is there any functional 

 adaptation from within? If a limb be not used 

 the bone will still grow more or less; but why 

 does the bone grow round? And an eye will 

 grow, from a germ of it, in the dark (Loeib). 

 Is there such a property in living matter as 

 " functional adaptation " ? Is function in its 

 effect upon form adaptive or purposive? Is 

 environment met by adaptive variation — for 

 instance in a germ cell? Again, if so, can 

 specific properties of such a kind be acquired? 

 Biologists seem to have proved that evolution 

 of form may go on continuously when environ- 

 mental change is suspended, or remains con- 

 stant; and conversely that environmental 

 change does not necessarily induce evolution. 

 On a broad view, says Professor Osborn,^ dur- 

 ing the infinite variety of the widely diverging 

 forms of the Mammalian period of the earth, 

 the reptiles have shown very little change. "We 

 3 Osborn, ' ' Origin and Evolution of Life, ' ' p. 

 137. 



perceive that these questions arise in some con- 

 trast with the hypothesis of the selection of 

 " chance " variations. 



On the other hand, we find reason to marvel 

 at the constancy of bacterial species; humble 

 and embryonic beings that we should not ex- 

 pect to have become fixed in their habits. Yet 

 they and their enzymes are very exacting about 

 it; as we find, for example, with the several 

 enteric bacteria, or with the meningococcic or 

 pneumococcic varieties, of which each has its 

 own serous or agglutinin test, and is indif- 

 ferent to the rest. And there is more still to 

 be said: when the microbe finds itself in the 

 host's body it may be wholly out of tune, or 

 wholly in tune, with any or all cells that it ap- 

 proaches; in either case presumably nothing 

 morbid would happen, perhaps, by a kind of 

 zygosis, a benefit; morbid happenings would 

 lie between this microbe and body cells within 

 its range but not in tune with it. Now there 

 seems to be reason to suppose that a microbe, 

 on its approach to a body cell only just out of 

 its range, may try this way and that to get a 

 hitch on. If so, the microbe, at first innocuous, 

 would become noxious. So on the other hand 

 body cells may educate themselves to vibrate 

 in harmony with a microbe before dissonant; 

 or there may be mutual interchange and co- 

 adaptation. Such considerations arise out of 

 many known phenomena at phase boundaries, 

 of sympathetic vibrations, of acquired im- 

 munity, of new virulences, and so forth; the 

 cells out of tune getting nearer and nearer into 

 consonance with each other. 



But, if things be so, surely we are face to 

 face with a marvelous and far-reaching fac- 

 ulty, the faculty of choice, and this rising from 

 the utter bottom of biology to the summit — 

 formative faculty — " auto-determination," or, 

 if you please, " mind." Can the microbe do as 

 the retriever does when with a hare in his 

 mouth he comes to a gate; he tries this way 

 and that, then thrusts the hare under the gate, 

 leaps over and pulls the hare through? So 

 the microbe tries it on, this way or that, till it 

 succeeds, by self-education in the school of 

 experience — Bildungstrieh. This is far more 

 : — radically more — than "elan vital " ; not 



