754 



SCIENCE. 



[N. S. Vol. XIX. No. 489. 



the comparative physiologist. Its bionomic 

 value is obviously great, for. it allows an 

 individual to utilize the experience of an- 

 other as well as its own. We might, in- 

 deed, compare it to the addition of a new 

 sense, so greatly does it extend the sources 

 of information. The communication be- 

 tween individuals is especially character- 

 istic of vertebrates, and in the higher mem- 

 bers of the subkingdom it plays a great 

 role in aiding the work of consciousness. 

 In man, owing to articulate speech, the fac- 

 tor of communication has acquired a maxi- 

 mum importance. The value of language, 

 our principal medium of communication, 

 lies in its aiding the adjustment of the in- 

 dividual and the race to external reality. 

 Human evolution is the continuance of 

 animal evolution, and in both the dominant 

 factor has been the increase of the re- 

 sources available for consciousness." 



Professor Minot believes that conscious- 

 ness is a real and dominant factor in the 

 evolution of animals, that it affects the vital 

 processes: "There is, in my opinion, no 

 possibility of avoiding the conclusion that 

 consciousness stands in immediate causal 

 relation with physiological processes." 



While I may not be ready forthwith to 

 admit that Minot 's dictum in regard to 

 consciousness is perfectly satisfactory, it 

 has been gratifying to me to find so many 

 views similar to those which I have been 

 myself accustomed for the past few years 

 to elaborate in my lectures to students, 

 expressed so clearly and vigorously in this 

 address. 



H. S. Jennings, who has worked much 

 on the reactions of infusoria, after criticiz- 

 ing the conclusions of Hodge and Aikins, 

 which he concludes go too far, refers to 

 Minot 's views. He thinks that by this 

 writer's criterion we should clearly have 

 to attribute consciousness to Stentor, for at 

 times this creature inhibits reactions to 

 stimuli, M'hile again it reacts strongly. 



Jennings is not, however, satisfied with 

 Minot 's criterion, for he believes that 'Un- 

 conscious mechanisms can be constructed 

 and, indeed, do exist, in which there is a 

 dislocation in time between the action of an 

 outer agent upon the machine and the re- 

 action of the machine similar to what we 

 find in organisms.' 



I can do but scant justice to a highly 

 critical, profound and suggestive paper by 

 H. Heath Bawden on 'The Psychological 

 Theoi-y of Organic Evolution.' He passes 

 in review the work of Binet, Cope, Loeb 

 and others. Professor Loeb lays stress on 

 what he terms 'associated memory,' by 

 which he means, 'that mechanism by which 

 a stimulus brings about not only the effects 

 which its nature and the specific structure 

 of the irritable organ calls for, but by 

 which it brings about also the effects of 

 other stimuli which formerly acted upon 

 the organism almost or quite simultane- 

 ously with the stimulus in question. ' Con- 

 sciousness ceases with 'associated memory,' 

 as in sleep, anesthesia, etc. According to 

 this test, Loeb fails to find consciousness in 

 infusoria, coelenterates and worms, and 

 doubtfully in many higher forms. He is 

 quite certain of consciousness only in many 

 of the higher vertebrates. Bawden thinks 

 Loeb errs, and while he believes that this 

 criterion may be good for determining the 

 degree of mammalian consciousness, he be- 

 lieves it too restricted to apply to the whole 

 animal kingdom, much less to the plant 

 world. Romanes held that 'consciousness 

 was that which enables the organism to 

 learn to make new adjustments or to 

 modify old ones in accordance with the re- 

 sults of its own individual experience.' 

 "Purposiveness means simple adaptation 

 of means to ends; consciousness means the 

 ability to vary the use of means to an end. 

 The former may be quite automatic, the 

 latter alone must be conscious" (Bawden). 



Baldwin savs, "Consciousness is the new 



