On the relation between the quantity of brain and the size of the body in vertebrates / by Eugène Dubois ; [communicated by H. Zwaardemaker].

Eugène Dubois

Date:: 1914

Credit: On the relation between the quantity of brain and the size of the body in vertebrates / by Eugène Dubois ; [communicated by H. Zwaardemaker]. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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$tJie braiti wi(h the mass ot the body, wiiliiji one species, as well as from species to species. Still it remains, however, an open ipiestion why the lengths of the images, as measured by the number of sense-elements, increase exactly as In order to tind an answer to it, we must consider, that the eye distinguishes itself fiom the other senses by giving at a distance a representation of the exact place of the e.nergy-soiirce that acts as a stimulus. Consequently it orientates about the direction from which tint stimulus comes. Object and image, that is the place of the stimulated sense-elements, answer to each other. Uiidei: these circumstances the distance to the objects must exactly stand in the mentioned relation to the linear dimension of the body. Indeed the receptive nerve-elements of the retina placed in the linear dimension of the image, increase then numerically in the propor- tion ot LO-33... ill iiiy 1^,1111,the linear dimension as their mass tor the surface of the image as L'\ But that mass determines the a.nountof the transition of energy that is connected with the stimulation of the sense-elements. It appears now that the long since known intimate connection of the organ ot vision, as exquisite sense of room finding its principal function in governing the movements, can be expressed in a definite measure 1). As ni the movements of animals, differing in the size of t leir bodies, Uie mass that is to be removed, increases in the pro- poition of L\ the muscle-jiower however only as L\ an Z-fold sensu-motorical stimulation is required for it. And as all senses are more or less, as the optical sense is absolutely, organs of room their receptive elements must, in the aggregate, increase in mass in’ in super- that proportion of L, that is in linear dimension as - 2 fieial dimension as iJ, or >5’^ But the nerve-fibres, the peripherical extremities of which are connected with sense-elements in the retina and also in all other sensitive surfaces, and the corresponding cell 9 2 masses in the brain must increase as [/S- = S^=z The denominator of the coeffleient A ea„ thus be explained as a^ relaUve reduction of llm brain of II,e larger animal |„oportio,ial B Id a sinking way this connection is demonstrated by Putter (1 c no 85 et seq, and p.p. 402 et seq). ^ ^$