292 SPECIAL PHYSIOLOGY. 



and causality, in the upper frontal region. The chief argument in 

 favor of any system of phrenology for several have been proposed 

 is, that the science has been deduced from the actual observation of 

 nature, that is, from a^ comparison, in very numerous instances, of the 

 form of the skull, which is taken to represent the form of the cere- 

 brum beneath it, with the propensities, moral feelings, and character, 

 the acquirements, and endowments, of the individual. There is noth- 

 ing irrational in the attempt to discover special organs in the brain 

 for the performance of special functions of the mind ; but the task is 

 not so easy as Gall and his school have imagined. To their systems 

 and method it has, indeed, been objected, that the instances of corre- 

 spondence with the craniographie schemes projected by Gall and 

 Spurzheim, and since modified and expanded by their followers, have 

 been mainly collected by partisans of craniology or phrenology ; that 

 no systematic investigations have been undertaken, by other and in- 

 dependent observers, to test the actual frequency of those correspond- 

 ences, or to detect any failures of such correspondence ; that, in many 

 instances, however, which have been noted, the most complete discrep- 

 ancy has existed between the local development of the cranium, and 

 the activity of the faculties or powers supposed to be exercised through 

 the agency of the subjacent parts of the brain ; and, lastly, that in 

 reference to any given faculty, one such well-marked caee of discrep- 

 ancy, is sufficient to shake the system, as regards that faculty, to its 

 foundation. It has, furthermore, not escaped the attention of the un- 

 biassed physiologist, that, in spite of a general resemblance between 

 the form of the cranium and that of the cerebrum beneath it, there 

 are many difficulties, such as the relative projection of the frontal, 

 parietal, and occipital eminences, the greater or less thickness of the 

 cranium, and the variable size of the frontal sinuses, in different indi- 

 viduals, which render it almost, if not quite impossible, to determine 

 accurately, degrees of local development of the parts beneath. More- 

 over, it has been shown by anatomists, that certain points or lines on 

 the surface of the hemispheres for example, the fissure of Rolando, 

 and the convolutions in front of and behind it do not invariably corre- 

 spond with the same parts or lines of the cranial walls ; but that, by 

 excess or diminution of development, in these or in neighboring parts, 

 they may shift their position backwards or forwards beneath the skull. 

 It has also to be noted, that the convoluted gray cortical substance of 

 the hemispheres, the supposed physiological seat of any force or faculty, 

 which these parts of the cerebrum may exert, is not limited to that 

 part of the cranial surface which is open to observation, nor, indeed, 

 to the inner surface of the cranium at all ; for it extends on each hemi- 

 sphere, to the frontal and temporal fossae, at the base of the skull, 

 and even to the upper surface of the tentorium ; and it likewise sinks 

 deeply into the longitudinal fissure, quite away from the skull itself, 

 and also into the Sylvian fissure, at the bottom of which, it forms the 

 central lobe, or island of Reil, a part completely concealed between 

 the overlapping edges of the frontal and parietal lobes. Lastly, no 

 external cranioscopical observations can determine the relative com- 

 plexity of the cerebral surfaces, nor the relative thickness of the gray 



