ARCHITECTURE. 197 



the region of the dorsal plate, but also an increase in both 

 the motor and sensory innervation of the body, especially 

 on the sensory side. 



The encephalon is by far the most interesting portion 

 of the nervous system, and therefore has been scrutinised 

 with the greatest care, even the folds which mark the 

 surface of the cerebrum having been studied in detail. 

 These folds, or gyri, are separated from one another by the 

 sulci or fissures. The questions which have been raised 

 concerning this feature are, first, whether the arrange- 

 ment of the folds is a constant one, and second, if it is 

 not constant, whether any conclusion can be drawn from 

 the variations which occur. At one time it was assumed 

 that variations in the intelligence could be measured by 

 this means, and that there was also a difference in these 

 folds according to sex. At present the question is also 

 discussed whether certain groups, criminals and the 

 insane for instance, have brains differently marked from 

 those of normal persons. Finally it has been thought 

 that the study of the brains of various races might bring 

 out important differences. The accompanying figures, 

 taken from Eberstaller J and Schafer, 2 represent the 

 appearance of a Western European brain ; that of 

 Eberstaller is the best schema of the lateral aspect that 

 has been published. By the aid of such a chart it has 

 been practicable to test the questions to which allusion 

 has just been made, but these tests have failed to 

 establish any constant peculiarities of fissuration charac- 

 teristic of sex, race, or social class. 



Since, however, the hemispheres of the brain are, in 

 the foetus, smooth, and only gradually become marked 

 by fissures, it is observed that early disturbances in their 

 growth, which later are almost invariably associated with 



1 Eberstaller, Das Stirnhirn, Vienna, 1890. 



2 Schafer, Quain's Anatomy, vol. iii. pt. i., 1893. 



