570 SIZE AND WEIGHT OF THE BRAIN. 



as the third year ; the Wenzels and Sir W. Hamilton fixed the period about the seventh , 

 and Tiedemann between the seventh and eighth years. Gall and Spurzheim were 

 of opinion that the brain continued to grow until the fortieth year. The observations 

 of Sims, Tiedemann, and Eeid, appear to show that in both sexes the weight of 

 the brain in general increases rapidly up to the seventh year, then more slowly to 

 between sixteen and twenty, and again more slowly to between thirty-one and forty, 

 at which time it reaches its maximum point. Beyond that period there appears a 

 slow but progressive diminution in weight of about 1 oz. during each subsequent 

 decennial period ; thus confirming the opinion that the brain diminishes in advanced 

 life. According to Peacock, the maximum weight of the brain is attained between 

 the ages of twenty and thirty years. The table of Boyd inserted above would appear 

 to show a somewhat earlier period as that at which the maximum is reached in both 

 sexes, and that the period of decline scarcely begins before sixty years. With this 

 result the observations of Huschke, made upon the brains of 359 men and 245 women, 

 in general agree. (" Schadel, Him, und Seele des Menschen und der Thiere, &c.," 

 1854.) 



All other circumstances being alike, the size of the brain appears to bear a general 

 relation to the mental power of the individual, although many instances occur in 

 which this rule is not applicable. The brain of Cuvier weighed upwards of 64 oz., and 

 there are other recorded examples of brains belonging to men of great talent which 

 nearly equalled it in weight. (Emille Rousseau, " Maladie et autopsie de M. G. Cuvier," 

 Lancette Franaise, Mai 26, 1832.) On the other hand, the brain in idiots is remark- 

 ably small. In three idiots, whose ages were sixteen, forty, and fifty years, Tiedemann 

 found the weight of their respective brains to be 19| oz., 25f oz., and 22^ oz; and 

 Dr. Sims records the case of a female idiot twelve years old, whose brain weighed 

 27 oz. Allen Thomson has found the brain of a dwarfish idiot girl seventeen years of 

 age to weigh 18^ oz. after preservation in alcohol. 



The human brain is found to be absolutely heavier than that of all the lower 

 animals except the elephant and whale. The brain of the elephant, according to 

 Perrault, Moulins, and Sir A. Cooper, weighs between 8 and 10 Ibs. ; whilst that 

 of the whale was found by Rudolphi, in a specimen 75 feet long, to weigh upwards 

 of 5 Ibs. 



The relative weight of the encephalon to the body is liable to great variation; 

 nevertheless, the facts to be gathered from the tables of Clendinning, Tiedemann, and 

 Reid, furnish this interesting general result. In a series of 81 males, the average 

 proportion between the weight of the brain and that of the body at the ages of twenty 

 years and upwards, was found to be as 1 to 36*5 ; and in a series of 82 females, to be 

 as 1 to 36 '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 appears 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 period 

 about Ito30. After the twentieth year, the general average of 1 to 36'5 prevails, 

 with a further trifling decrease in advanced 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 small birds, 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 parts of the cerebrum to each other and to the degree of intelli- 

 gence, either more directly or by the cranioscopic methods, have as yet been attended 

 with 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 between 

 the brains of certain persons of known intelligence, cultivation, and mental power, 

 and those of persons of an ordinary or lower grade. As examples of brains of men of 



