Brain Size

Abstract

IN his book, The Growth of the Brain, published in 1895, Donaldson¹ collected an important mass of data on the size of vertebrate brains. On page 123 he succinctly states: While the large absolute weight of the brain in man as compared with other animals still demands interpretation, it is evident from the foregoing facts that conclusions based upon the proportional development of the brain may be very easily misleading, because the variation in that proportion depends upon differences in body weight. In reality there is here an extremely complex problem, and although in the estimation of the probable intelligence of any animal both the absolute and relative size of the brain are factors, yet they are but two factors among a large number, and therefore, their importance can only be determined after further analysis and comparison. Such further analysis is the goal of the present contribution. To