TO RELATIVE CAPACITY OF RACES. 183 



of human crania furnish reliable series of data, each uniform in 

 system, and sufficiently minute to satisfy many requirements of com- 

 parative craniometry. 



Without assuming an invariable correspondence in cubical capacity 

 and braia-weight, there is a sufficient approximation in the cubical 

 capacity of the skull and the average weight of the encephalon to 

 render the deductions derived from gauging the capacities of skulls 

 of different races an important addition to this department of com- 

 parative ethnology. For minute cerebral comparisons, however, it 

 is apparent that much more is required ; and the special functions 

 assigned to the various organs within the cranium have to be kept in 

 view. Of these the medulla oblongata, in direct contact with the 

 spinal cord, is now recognized as the centre of the vital actions in 

 breathing and swallowing \ and is believed also to be the direct source 

 of the muscular action employed in speech. Next to it are the sensory 

 ganglia, arranged in pairs along the base of the brain. To the cere- 

 bellum, which the phrenologist sets apart as the source of the emotions 

 and passions embraced in his terminology of amativeness, philo- 

 progenitiveness, &c., physiologists now assign the function of con- 

 veying to the mind the conditions of tension and relaxation of the 

 muscles, and so controlling their voluntary action. But above all 

 those is the cerebrum, or brain-proper, consisting of two large lobes 

 of nervous siibstance, which in man are so large that, when viewed 

 vertically, they cover and conceal the cerebellum. To this organ is 

 specially assigned emotion, volition, and ratiocination. It is the 

 assumed seat of the mind ; and, in a truer sense than the skull, 



"The dome of thought, the palace of the soul;" 

 if indeed it be not, to one class of reasoners, the mind itself. Certain 

 it is that no acute disease can affect it without a corresponding dis- 

 order of the functions of mind ; and with this organ much below the 

 average size, intellectual weakness may always be predicated. But a.t 

 the same time, it is significant to note that the human brain, stinted 

 in its full proportions, and reduced to a seeming equality with the 

 anthropomorpha., exhibits no corresj^onding capacities or instincts in 

 lieu of the higher mental qualities. Microcephaly is the invariable 

 index, not of mere limited intelligence and mental capacity, but of 

 actual mental imbecility. If the augmentation of the brain of the 

 anthropomorpha from 55 to 115 cubic inches be all that is requisite 

 for the transformation of the irrational ape into the reasoning man, 



