424 SECTIONAL TRANSACTIONS.—D. 
but of instinctive behaviour, or, in other words, instinctive response to a 
stimulus or complex of stimuli. 
Can we distinguish instinctive from other behaviour? Most psychologists 
seem to draw a distinction, sometimes a sharp one, between instinctive and 
intelligent behaviour. But I have looked in vain for any definition of the 
one which will exclude the other. 
The most generally accepted view seems to be that instinctive behaviour 
depends on an inherited mechanism (variously called innate dispositions, con- 
genital prearrangements, and the like), while intelligent behaviour depends on 
experience acquired during the lifetime of the individual. Instinctive behaviour 
is said to be the working of a preformed mechanism set going by an appropriate 
veleasing stimulus, and therefore to be definite, relatively invariable, inherited. 
Intelligent behaviour is contrasted as indefinite, variable, not inherited but 
acquired. 
But all behaviour is made up of responses, and these, like structural responses 
or character, all depend, on the one hand, on transmitted factors of inheritance, 
and, on the other, on the moulding conditions of the environment. As I tried 
to show in my Presidential Address, a response can never be transmitted in 
inheritance as such, nor can it occur unless both the necessary conditions and 
the transmitted factors are present. Instinctive response is neither more nor 
less acquired than intelligent response. What is the innate mechanism, said 
to be inherited, but the result of reactions to internal as well as external 
environmental conditions; the product of the past experience of the individual 
in which it is developed (using the word ‘ experience’ as a biologist and not 
as a metaphysician)? There is no hard and fast line to be drawn between 
intelligent and instinctive behaviour. In so far as it depends on a mechanism 
yielding a closely interlocked series of reactions specialised and adapted to 
respond in one direction to a particular evocative stimulus, behaviour may be 
said to be instinctive. In so far as it depends on a mechanism delicately 
balanced so as to respond in a variety of ways to environmental stimuli differing 
perhaps only slightly in nature and intensity, behaviour may be said to be 
intelligent. Instinctive behaviour corresponds to what we call constancy of 
structure in bodily characters ; intelligent behaviour to modifiability or individual 
adaptability. 
Prof. J. ArrHuR THomson.—(1) Is it possible to distinguish different grades 
of instinctive behaviour, e.g., from bee to bird? (2) If instinctive behaviour, 
physiologically regarded, is made up of a succession of reflex actions, what, 
evidence can be adduced in support of the view that there is sometimes a 
subjective aspect of appreciative awareness and endeavour? (3) May one 
venture to suggest a provisional diagram of the inclined plane of animal 
behaviour ? 
17. Mr. F. A. Porrs.—The Work of the Carnegie Institution of Wash- 
ington in the Pacific. 
The Department of Marine Biology of the above institution has, apart from 
its essential work in the West Indies, conducted a series of expeditions in the 
Pacific. In 1913 Dr. Mayer made an intensive study of Murray Island in 
Torres Straits. During the last few years the work, in which a number of 
specialists have engaged, has centred round the island of Tutuila in the Samoan 
group. The Samoan reefs are not so rich as the Great Barrier Reef, but in 
the harbour of Pago Pago, Tutuila, the best conditions occur for the study of 
coral reefs. Exhaustive experiments on the rate of growth of corals and the 
influence of varying conditions have been made. The reefs have been explored 
by diving, and the habits and colouration of the fish fauna studied by this 
method. The reef has been drilled in ceveral places and a great deal of 
attention has been devoted to the geological history and the botany. 
18, Prof. Georcz H. Carpenter.—Warble-flies: a Study in Develop- 
ment and Adaptation. 
The later stages in the life-history of the Warble-flies (Hypoderma) of 
cattle have been well known since the researches of Bracy Clark early last 
century. Only during the last few years, however, has it been shown—by 
Hadwen in Canada, Glaser in Germany, and the writer and, his colleagues in. 
et OO ———————— 
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