244 



volumes to Hie volumes of houiologous ÏI er V e or g a n g 1 i n cells, 

 bolh between adult individnal.s of one species and between different 

 species. This confirms that, witli increasing bodj weight, froin adult 

 individual to adult individual of one and the same species, only 

 the V 1 u m e of each nerve cell in the brain increases, but from 

 species to species at the same time the number of these cells, and 

 that the number does so in the same ratio as the volume incieases, which 

 had already been rendered probable bj other facts. Comparison of 

 the biain weight in function of the body weight between the two 

 sexes*) had led me to the result, on the ground of the measurements 

 of the diameter of the muscle fibres by Bowman and by Schvvalbe 

 and Mayeda, and the observations of muscle weights by Theilb, 

 that the number of muscle fibres of Man is equal to that of Woman. 

 From the couiparison of the relative quantity of brain and musculaiity 

 of the Europeans and the Japanese it had appeared to me that the 

 relatively larger volume of the brain and of the muscles of the 

 latter finds its explanation, not in the different number of the neu- 

 rones and the muscle fibres, but in the larger cross-section of the 

 separate muscle fibres, larger separate volume of the nerve cells '). 

 Hence, between Man and Woman, between the Japanese and 

 the European, i. e. within the species of Homo sapiens, only the 

 volume, not the number of the nerve cells and of the muscle 

 fibres differ. 



the Fox, 52 gr. for its brain weight; the average body weight of the eleven 

 domestic dogs is 6.6 kg., tlieir average brain weight 68 gr. Hence with equal 

 body weight, the latter brain weight is 28.4% more than for the Fox. Compa- 

 rison of these dogs with the jackals (Qanis aureus) leads to similar results. The 

 average body weight of fourteen jackals according to Klatt's observations (Haupt- 

 tabelle) is 6.836 kg., their average brain weight 57.1 gr. The difference with dogs 

 of the some body weight is 20.1 '^/,„ somewhat less than the difference of these 

 with the Fox, because the cephalisation of the Jackal is a little higher. In contrast 

 with domestic dogs of the size of these small Canidae, domestic dogs of the size 

 of the Wolf have 24.8% less brain than averagely this largest species of the 

 genus Ganis. From Klatt's records .(Haupttabelle) of brain weights of six and 

 body weights of four Lapland and Russian wolves, and of cranial capacities of 

 23 European and American wolves (Klatt. Ueber die Veranderung der Schadel- 

 kapazitat, p. 166), averagely 161 c.c, 1 derived a body weight of the species of 

 40 kg., a brain weight of 147.6 gr. Absolutely both weights may be a little 

 too high, relatively most likely they are about right. Accordingly the Wolf is 

 about equal in its cephalisation with the Fox. But twenty dogs of Klatt's observa- 

 tions, of 30 to 48 kg., averagely 37.6 kg. body weight, have an average brain 

 weight of 109.4 gr. 



1) Under this title in these Proceedings, Vol. XXI, p. 868—869. (1919). 



2) EuG. Dubois, On the Significance of the Large Cranial Capacity of Homo 

 neandertalensis. These Proceedings, Vol. XXIU, p. 1281. (1921). 



