580 ENCEPHALON. 



and Eeid, furnish this intei'esting general result. In a series of SI males, the 

 average proportion between the %veight of the brain and that of the body at 

 the ages of twenty years and upwards, was found to he as 1 to SG'o ; and 

 in a series of 82 females, to be as 1 to 3G'46. In these cases the deaths were 

 the result of more or less prolonged disease ; but in six previously healthy 

 males, who died suddenly from disease or accident, the average proportion was 

 1 to 40-8. 



The proportionate weight of the brain to that of the body is much greater at 

 birth than at any other period of life, being, according to Tiedemann. about 1 to 

 5'85 in the male, and about 1 to 6'5 in the female. From the observations already 

 referred to, it further apjjears that the proportion diminishes gradually up to 

 the tenth year, being then about 1 to 14. From the tenth to the twentieth 

 year, the relative increase of the body is most striking, the ratio of the two 

 being at the end of that i^eriod about 1 to 30. After the twentieth year, the 

 general average of 1 to 36'5 prevails, with a fm-ther trifling decrease in ad- 

 vanced life. 



Viewed in relation to the weight of his body, the brain of man may be stated 

 generally to be heavier than the brains of the lower animals ; but there are 

 some exceptions to the rule, as in the case of certain species of smaU bu-ds, in 

 the smaller apes, and in some small rodent animals. 



The attempts hitherto made to measure or estimate the relative proportions 

 of the different convoluted jDarts of the cerebram to each other and to the 

 degree of intelligence, either more directly or by the cranioscopic methods, have 

 been attended -ndth little success. The more recent researches of Rudolph 

 "Wagner, which have been farther prosecuted by his son. hold out some promise, 

 when fully carried out. to afford more definite results. 



These researches had for their object to institute an accurate comparison be- 

 tween the brains of certain persons of known intelligence, cultivation, and 

 mental power, and those of i^ersons of an ordinary or lower grade. As exam- 

 isles of brains of men of superior intellect, he selected those of Professor Gauss, 

 a well-known mathematician of eminence, and Professor Fuchs, a clinical 

 teacher ; and as examples of brams of ordinary persons, those of a woman of 

 20 and a workman named Krebs. all of which he examined and measTU'ed with 

 scrupulous care. 



The general result of R. "Wagner's researches upon these and other brains may 

 be stated to be as follows. 1st. Although the greatest number of brains belong- 

 ing to men of superior intellect are found to be heaviest or largest, yet there 

 are so nianj- instances in Vv^hich the brains of such persons have not suriiassed, 

 or have even fallen below the average size of the brains of ordinary persons, 

 that superiority of size cannot in the present state of our knowledge be regarded 

 as a constant accomjianiment of superiority of intellect, even when due regard 

 has been paid to the comparative stature and other cii-cumstances of the in- 

 dividuals. 



2nd. It would appear that, ui the brains of certain persons of superior intellect, 

 the cerebral convolutions have been found more numerous and more deeply 

 divided than in those of i^ersons of ordinary mental endo\\nnents and without 

 cultivation. But numerous exceptional instances are also found of paucity of 

 convolutions coincident with superior intellect, which make it impossible at 

 present to deduce any certain conclusion with respect to the relation between, 

 the number or extent of the convolutions and the .intellectual manifestations 

 in different persons. 



The careful measurement of all the convolutions and the intervening grooves 

 in the four brains above mentioned has been carried out by the younger "Wagner, 

 and the tables and results of these measurements published by hun as an 

 appendix to his fathers treatise. (Hermann "Wagner, " Maasbestimmungen der 

 Oberflache des Grossen Gehims," &c., Cassel und Gottingen, 1864.) 



The following short table extracted from Hermann "Wagner's memoir, and 

 simplified by the omission of small fractions and by the reduction of the mea- 

 surements from square millimetres to English square inches, may give the reader 

 some idea of the natiu-e of the inquiry. 



