122 Amer. J. of Anatomy, VIII, pp. 319ã353, 1908. Donaldson (Journ. Comp. Neur. and Psychol. XVIII, pp. 345ã392, 1908) also gives a logarithmic formula for brain-weight (y) as compared with body-weight (x), which in the case of the white rat is y =ã₤ôñ554ã₤ãã₤ôñ569 log(xã₤ãã₤8ôñ7), and the agreement is very close. But the formula is admittedly empirical and as Raymond Pearl says (Amer. Nat. 1909, p. 303), ãno ulterior biological significance is to be attached to it.ã
123 Biometrika, IV, pp. 13ã104, 1904.
124 Donaldson, H. H., A Comparison of the White Rat with Man in respect to the Growth of the entire Body, Boas Memorial Vol., New York, 1906, pp. 5ã26.
125 Besides many papers quoted by Dubois on the growth and weight of the brain, and numerous papers in Biometrika, see also the following: Ziehen, Th., Das Gehirn: MassverhûÊltnisse, in Bardelebenãs Handb. der Anat. des Menschen, IV, pp. 353ã386, 1899. Spitzka, E. A., Brain-weight of Animals with special reference to the Weight of the Brain in the Macaque Monkey, J. Comp. Neurol. XIII, pp. 9ã17, 1903. Warneke, P., Mitteilung neuer Gehirn und KûÑrperôÙgewichtsôÙbestimôÙmungen bei SûÊugern, nebst Zusammenstellung der gesammten bisher beobachteten absoluten und relativen Gehirngewichte bei den verschiedenen Species, J. f. Psychol. u. Neurol. XIII, pp. 355ã403, 1909. Donaldson, H. H., On the regular seasonal Changes in the relative Weight of the Central Nervous System of the Leopard Frog, Journ. of Morph. XXII, pp. 663ã694, 1911.
126 Cf. Jenkinson, Growth, Variability and Correlation in Young Trout, Biometrika, VIII, pp. 444ã455, 1912.