Vol. 65.] ANNIVERSARY ADDRESS OP THE PRESIDENT. CXX1 



the Mammalia has been greater than in the case of the horse. The 

 human family, which seems to be of surprisingly recent origin, 

 may be one of these, at least as regards the phylogenetic growth of 

 the brain. The earliest human skulls known to us are those of the 

 Neandertal race, with a capacity of about 1250 cubic centimetres. 1 

 This was the volume of the human brain, so far as is known, 

 during the Mousterian age ; in the Magdalenian it had become 

 1550 c.c, an increase of 300 c.c. which occurred during the interval 

 represented by the Upper Palaeolithic deposits. At present we havo 

 no means of estimating, even approximately, the value of this 

 interval in years. For the sake of illustration we will suppose it 

 to be 30,000 years, or three times the interval which separates cis 

 from the early civilization of Egypt. In the case of the horse 

 we made use of linear measurements and, to be consistent, we will 

 do so now. It will be sufficient for our purpose, if we regard the 

 skull as a cubical box : with a capacity of 1250 c.c, this would 

 measure internally 10*772 cms. along the edge ; with a capacity 

 of 1550 c,c, it would measure 11*573 cms., a difference of 8 mms., 

 and this measures the increase which would be effected in the 

 course say of 30,000 years. The rate of change is 0*024 mm. 

 per century, or 0*008 mm. per generation of 30 years, an almost 

 inappreciable quantity which would certainly have escaped the 

 attention of contemporary observers. 



But the pakeontological record reveals only few traces of the 

 successive stages of human evolution ; we have, it is true, the 

 intermediate horizon of the Solutrian, and corresponding skulls 

 possibly of 1450 c.c. capacity ; but there are none of those nicely 

 graduated examples such as we should expect if the record were 

 more complete, or if a continuous evolution had proceeded within 

 the European area. The theatre of change was probably situated 



[* Since correcting the proofs of the Address I have examined, under the 

 guidance of Prof. Marcellin Boule, the Neandertal skull lately discovered at 

 La Chapelle aux Saints. Its general appearance suggests a large volume, and 

 Prof. Boule informed me that according to his measurements its capacity is 

 1600 c.c. It is the occipital region which appears to be the most developed, 

 and the frontal lobes may be disproportionately small. A cast of the interior 

 which Prof. Boule proposes to obtain will afford more definite information on 

 this and related points. After seeing this skull, I should have liked to delete 

 all that appears here relating to the evolution of Man, and am only restrained 

 by a feeling of fairness. It may stand to point a moral. — W. J. S., Maij 12th, 

 1909.] 



VOL. LXV. * 



