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

  • Dubois, Eugène, 1858-1940.
Date:
1914
Catalogue details

Licence: In copyright

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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    in this wa} the required measure for the organisation of the nervons system cannot be found, but on the contrary false relations are obtained. Then Man is indeed not only inferior to some small Monkeys but even to the Mouse. Tlie latter would then be four times better provided with brain than the Brown Rat, and the Cat five times better than the Tiger or the Lion. In general we tind, not only in Mammals, but in all Verte- brates, that the smaller species of closely allied animals, i-elatively to the weight of their bodies, have a great quantity of brain. If we exclude, however, as much as possible, the above mentioned factors which, besides the size of the body, influence the quantity of brain, if we tlius compare animals taken in the state of nature, which are as near as possible to one another, systematically, in their manner of life and in the shape of their bodies, but differ as much as possible in the size of their bodies, then it must be possible, to discover at least, if it is not a simple proportion, some relation existing between the quantity or mass of brain and the size, the weight of the body. Abont twenty years ago the necessary, trustworth}^ evidences, chosen and explained with critical discernme]if, were very rare. Thankfully it may be remembered here that it was Max Weber, who, by procuring them, was one of the first that prepared the way for the treatment of this problem, at least in so far as regards Mammals ^). At all events the size of the body remains a very important factor amongst those determining the quantity of brain, for the Lion e. g. possesses absolutely 7 limes as much brain as the Cat, the Brown Rat 6 times as much as the Mouse. Evidently the weight of the brain is, after all, a (mathematical) function of the weight of the body. If the quantity of brain does not increase proportionally to the volume of the body, expressed by the weight, it might be that this is really the case with regard to the superficial dimensions, as being- proportional witli the receptive sensitive surfaces and with the sections of the muscles, thus measuring the passive and active relations of the animal to the outer world, for which in this way the quantity of brain can be a measure. Then, in animals equal in organisation and shape, but not in size, the (jnantities of brain must increase as 2 the — power or the power 0.6B.. of the weights of the bodies. In those comparable Vertebrates of different sizes the longitu- dinal dimension might likewise be the measure of the (juantity of q Especially in his “Vorsludien uber dus Hirngewiclit der Saugetliiere”. Fest- schrift fdr Carl Gegenbaur. Leipzig 1896.