444 



NATURE 



[September 22, 1923 



to concentrate its attention upon the thinj; seen rather 

 than upon the muscular act incidental to the pro<css 

 of seeing it. This represents the germ of attention and 

 of mental concentration in general, liut the {x^wcr of 

 automatically moving the eyes with such accuracy 

 that the images of an object upon the two retina* could 

 be focussed with precision upon exactly corresponding 

 spots made ]}ossible the ac(|uisition of stereoscopic 

 vision, the ability to appreciate the form, size, solidity, 

 and exact position in space of objects. It also pre- 

 pared the way for the development in each retina of a 

 particularly sensitive spot, the macula lutea, which 

 enabled the animal to appreciate the texture, colour, 

 and other details of objects seen with much more pre- 

 cision than before. Hence probably for the first time 

 in the history of living creatures an animal acquired 

 the power of " seeing " in the sense that we associate 

 with that verb. The attainment of these new powers 

 of exact vision further stimulated the animal's curiosity 

 to examine and handle the objects around it and pro- 

 vided a more efficient control of the hands, so that acts 

 of increasing degrees of skill were learned and much 

 more delicate powers of tactile discrimination were 

 acquired. Out of these experiments also there emerged 

 a fuller appreciation of the nature of the objects seen 

 and handled and of the natural forces that influenced 

 the course of events. 



With the acquisition of this new power of learning 

 by experimentation, events in the world around the 

 animal acquired a fuller meaning ; and this enriched 

 all its experience, not merely that which appealed to 

 the senses of sight and touch, but hearing also. Thus 

 in the series of Primates there is a sudden expansion of 

 the acoustic cortex as soon as stereoscopic vision is 

 acquired, and the visual, tactile, motor and prefrontal 

 cortex also feel the stimulus and begin rapidly to ex- 

 pand. This increase of the auditory territory is ex- 

 pressed not only in a marked increase of acoustic 

 discrimination but also by an increase in the power of 

 vocal expression. At a much later stage of evolution 

 the fuller cultivation of these powers conferred upon 

 their possessors the ability to devise an acoustic sym- 

 bolism capable of. a much wider range of usefulness than 

 merely conveying from one individual to another cries 

 expressive of different emotions. For when true arti- 

 culate speech was acquired it became possible to con- 

 vey ideas and the results of experience from individual 

 to individual, and so to accumulate knowledge and 

 transmit it from one generation to another. This 

 achievement was probably distinctive of the attainment 

 of human rank, for the casts obtained from the most 

 primitive brain-cases, such as those of Pithecanthropus 

 and Eoanthropus, reveal the significant expansion of 



the acoustic cortex. This new power exerted the most 

 profound influence upon human Iwhaviour, for it made 

 it possible for most men to lxr<<>me subject to traditiun 

 and to ac(juire knowledge from their fellows withoui 

 the necessity of thinking and devising of thnr <<\k\\ 

 initiative. It is easier to behave in the r; 

 by convention than to originate action •: . 

 special circumstances. 



Within the limits of the human family itself thi 

 progressive series of changes that we have witiiesse<l 

 m man's Primate ancestors still continue ; and as we 

 compare such a series of endocranial casts as those of 

 Pithecanthropus, Eoanthropus, Homorhodesiensis, Homo 

 neanderthalensis , and Homo sapiens, we can detect a 

 progressive expansion of the parietal, prefrontal, and 

 temporal territories, which are associated with the 

 increasing powers of manual dexterity and discrimina- 

 tive power, of mental concentration and of acoustic 

 discrimination. 



The study of such factors of cerebral development 

 will eventually enable us to link up the facts of com- 

 parative anatomy with psychology, and enable us the 

 better to understand human beha\Tiour. Such wider 

 knowledge will, in time, help us to co-ordinate the 

 principles that underlie customs and beliefs, and 

 from such researches there will eventually emerge 

 a distinctive discipline and a more strictly scientific 

 method. 



For the full realisation of this vision, what is necessar\- 

 above all is that the universities should recognise the 

 importance of this new conception of humane studies 

 and take an active part in building up a science of 

 man that is more scientific than what at present are 

 known as the humanities and more human than 

 biolog}\ The fundamental aim of all education is the 

 fuller understanding of the forces of Nature and of 

 human behaviour. The necessity for attacking the 

 latter problem with more directness and precision is 

 urgent ; and it is imf)ossible to exaggerate the impjort- 

 ance of a fuller cultivation in our universities of the 

 study of the nature of man and of the springs of human 

 conduct. It lies at the root of all knowledge and the 

 intelligent control of all human affairs. I need not 

 emphasise the tremendous practical importance of 

 such studies to an Empire such as ours at the present 

 time. The Pan-Pacific Conference held in Australia 

 recently is an earnest of the realisation of this fact 

 by statesmen and administrators and of the usefulness 

 of collaborating with men of science to acquire an 

 understanding of subject peoples and their social 

 problems. This policy of peaceful development of 

 the Pacific is a good augur}- for the fuller recogni- 

 tion of the value of anthropolog>' to the world at large. 



Some Bearings of Zoology on Human Welfare.^ 

 By Prof. J. H. Ashworth, D.Sc, F.R.S. 



T^HE bearings of zoology on human welfare — as 



J- illustrated by the relation of insects, protozoa, 



and helminthes to the spread or causation of disease in 



man — have become increasingly evident in these later 



* From the presidential address delivered to Section D (Zoology) of the 

 Bntish Association at Liverpool on September 13. 



NO. 2812, VOL. 112] 



years, and are familiar to even.- student of zoology- or 

 of medicine. At the time of the last meeting of the 

 British Association in Liverpool (1896), insects were 

 suspected of acting as transmitters of certain patho- 

 genic organisms to man, but these cases were few, and 

 in no single instance had the life-cycle of the organism 



