904 REPORT — 1900. 



multiplied by 100 and divided by length, measured in tbe manner indicated, gives 

 the true sacral index. 



The curvature of the sacrum may be conveniently plotted by taking a tracing 

 from a strip of soft metal which has been previously adapted by pressure to the 

 front of the sacrum along its middle line. The index of curvature may be ex- 

 pressed by tbe number derived by multiplying tbe height of this plotted curve 

 by 100 and dividing by the number corresponding to the true length of the 

 sacrum. 



.5. On the Microceplialic Brain. 

 By Professor D. J. Cunningham, M.D., F.R.S. 



The brain of the microcephalic idiot may exhibit features which do not merely 

 represent a 'fixed' embryonic condition. In one specimen the arrangement of 

 the fissures and sulci is found to approach more closely the ape than the human 

 type, and in almost every furrow some simian character can be detected. These 

 simian characters must not be considered mere foetal conditions rendered per- 

 manent. The ape-like condition existing in this brain does not as a whole 

 correspond to that of any one ape, or group of apes, but there is a complicated 

 mixture of features some of which are characteristic of high apes, while others 

 find a parallel in the brain of low apes. The microcephalic brain maybe regarded 

 as a partial ' atavism.' So far as its surface markings are concerned the specimen 

 noted has reverted in part, or wholly, to an arrangement which, in all probability, 

 existed in some early stem -form of man. 



6. DeveloiJmental Changes in the Human Skeleton from the Point of View 

 of Anthropology. By David Waterston, M.D., F.R.C.S.E. 



A series of specimens of the long bones of the extremities at different ages of 

 embryonic and infantile life has been collected and examined. The methods 

 employed in the examination were those of anthropometry, namely, osteometry 

 and osteoscopy. 



By the former, the relative lengths of the bones of the limbs at different ages 

 have been ascertained and compared one with another, and by the latter it has 

 been found that these bones present some definite and interesting characters. 

 Without going minutely into the rate of growth of each segment of the upper and 

 lower limbs, the general character was shown, and the special features of the 

 bones at different ages were demonstrated by means of lantern slides taken from 

 photographs of the objects. An attempt has also been made to ascertain the 

 cause of the special characters found in the bones by investigating the time of 

 their appearance and of their replacement by adult characters. 



A comp.arison has also been instituted between the bones of the embryo and 

 those of the lower races of mankind and of the higher apes, both as regards their 

 relative length and their characters. 



As it has been shown that the curvature of the spine in the lumbar region is a 

 post-natal development, and one adapted to the assumption of th.e erect attitude 

 by the infant, it was shown that in a similar way the configuration of the bones 

 of the lower extremity alters after birth, before the infant can stand erect. 



MONDAY, SEPTEMBER ]0. 



The following Papers and Report were read : — 



1. On the Imperfection of our Knowledge of the Black Races of the Trans- 

 vaal and the Orange River Colony. By E. S. Hartland, F.S.A. 



Our information on the customs, institutions, and beliefs of the native races of 

 the Transvaal and the Orange River Colony is derived chiefly from fragmentary 



