THE DEVELOPMENT OV SKULL AND BRAINS, €49 



only gives us important information as to brain form, but l)j affording 

 a comparison between the external and internal surfaces of the cranial 

 wall it gives a valuable clew to the real significance of the external 

 configuration. Beyond determining its capacit^^ we can do but little 

 toward an exact investigation of the cranial cavity without making a 

 section of the skull. Forty 3'ears ago Professor Huxley, in his work 

 On the Evidence of Man's Place in Nature, showed the importance of 

 a comparison of the basal with the vaulted portion of the skull, and 

 maintained that until it should become "an opprobrium to an ethno- 

 logical collection to possess a single skull which is not \bisected longi- 

 tudinally' there would be "no safe basis for that ethnological 

 craniology' which aspires to give the anatomical characters of the 

 crania of the diti'erent races of mankind." Professor Cleland and Sir 

 William Turner have also insisted upon this method of examination, 

 and only two ^a^ars ago Prof. D. J. Cunningham, in his pi'esidential 

 address to this section, quoted with approval the forcible language of 

 Huxley. The curators of craniological collections appear, however, to 

 possess an invincible objection to any such treatment of the specimens 

 under their care. Even in the Hunterian Museum in London, where 

 Huxlev himself Avorked at this subject, among several thousands of 

 skulls, scarcely an}' have been bisected longitudinally or had the 

 cranial cavit}^ exposed by a section in any other direction. The 

 method advocated so stronglv by Huxley is not onl}' essential to a 

 thorough study of the relations of basi-cranial axis to the \'ault of the 

 cranium and to the facial portion of the skull, but also permits of 

 casts being taken of the cranial cavity, a procedure which, I would 

 venture to suggest, has been too much neglected by craniologists. 



Every student of anatomy is familiar with the finger-like depressions 

 on the inner surface of the cranial wall, which are described as the 

 impress of the cerebral convolutions; but their exact distril)ution and 

 the degree to which they are developed according to age, sex, race, 

 etc., still remain to be definitel}" determined. Indeed, there appears 

 to be a considerable difference of opinion as to the degree of approxi- 

 mation of the outer surface of the brain to the inner surface of the 

 cranial wall. Thus the brain is frequently described as lying upon a 

 water bed, or as swimming in the cerebro-spinal fluid, while Hyrtle 

 speaks of this fluid as a "ligamentum suspensorium"'' for the brain. 

 Such descriptions are misleading when applied to the relation of the 

 cerebral convolutions to the skull. There arc, it is true, certain parts 

 of the l)rain which are surrounded and separated from the skidl by a 

 considerable amount of fluid. These, however, are mainly the lower 

 portions, such as the medu la oblongata and pons Varolii, which may 

 be regarded as prolongatiorrs of the spinal cord into the cranial cavity. 

 As they contain the centers controlling the action of the circulatory 

 and respiratory organs, thej are the most vital parts of the central 



