THE BRAIN THE ORGAN OF THE MENTAL FACULTIES. 305 



"Let it not be believed," says a distinguished writer, 1 "an affair of 

 accident, that a head" of considerable dimensions is found, from time to 

 time, to coincide with a distinguished genius. Although the amour 

 propre may object, the law is general. I have neither met in antiquity, 

 nor in modern times a man of vast genius, whose head ought not to be 

 ranged in the latter class, which I have just established, especially if 

 attention be paid to the great developement of the forehead. Look at 

 the busts and engravings of Homer, Socrates, Plato, Demosthenes, 

 Pliny, Bacon, Sully, Galileo, Montaigne, Corneille, Racine, Bossuet, 

 Newton, Leibnitz, Locke, Pascal, Boerhaave, Haller, Montesquieu, 

 Voltaire, J. J. Rousseau, Franklin, Diderot, Stoll, Kant, Schiller, &c." 

 Yet we are not always accurate in estimating the size of the brain 

 from the developement of the head. Dr. Sewall 2 has clearly shown, 

 that skulls of the same dimensions, as measured by the craniometer, 

 differ largely as to the quantity of cerebral substance, which they are 

 capable of containing. With the assistance of Dr. Thomas P. Jones, of 

 Washington, and of Professor Ruggles, of the Columbian College, he 

 instituted various experiments. In the first series, he ascertained the 

 volume of each skull, brain included : in the second series, the volume 

 of the brain alone or the capacity of the cerebral cavity ; and in order 

 to render the difference in capacity more obvious, the volume of each 

 skull, brain included, was reduced to the dimensions of 70 fluidounces. 

 The results of the experiments on five skulls, delineated in the plates 

 of Dr. Sewall's work, were as follows : 



In two of these skulls, consequently, of the same external dimen- 

 sions, there was a difference in the volume of brain of 31-89 oz. Dr. 

 Sewall infers from his observations, that no phrenologist, however ex- 

 perienced, can, by any inspection of the living head, ascertain whether 

 a person has a skull of one inch or one-eighth of an inch in thickness ; 

 or whether he has 56-22 ounces of brain, or only 25-33 ounces. 



To the view, that the mental capacity is in a ratio with the size of the 

 brain there must be numerous exceptions ; for, independently of bulk, 

 there may obviously be an organization productive of results, in which 

 the largely developed organ may be greatly deficient. Size is only one 

 of the elements of activity of an organ. " Whilst there is an evident 

 connexion," says a recent writer, 3 "between a large quantity of cere- 

 bral matter, and a highly developed intellect, the quality of the mind 

 and that of the brain-substance may also be supposed to have a close 

 relation to each other. In great power of action a large muscle is 

 needed, but for vigorous and well-adjusted muscular movement a cer- 



1 Gall, Sur les Fonctions du Cerveau, ii. 342, Paris, 1825. 



a An Examination of Phrenology, in Two Lectures, 2d edit., p. 66, Boston, 1839. 



3 Todd and Bowman, The Physiological Anatomy and Physiology of Man, p. 262, Lond., 1845. 



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