Page:Popular Science Monthly Volume 31.djvu/372

logical, therefore, to conclude that no parallel exists between power of mind and weight of brain.

M. Nikiforoff, a Russian scientist, in an article in the "Novosti," on the weight of brains, expresses his conviction that the weight of the encephalon has no influence whatever on the mental faculties. But, indeed, any reflecting person who has studied the brain-weights of eminent men as compared with ordinary intelligences must arrive at the same conclusion—that a great mind may belong to a person who carries a very small, a medium-sized, or a very large brain, the size and weight neither adding to the mental power nor detracting from it, provided only that the encephalon is sufficient to give due support to the bodily life. And this leads us to note the relation of the size of the brain to the size of the body of which it forms a part.

The following table is taken from the second volume of the "Science and Practice of Medicine" (London, 1868). Its object is to show the weight of the brain relatively to the weight and height of the body at various ages and in both sexes:

 

AGE.		Sex.	Weight of body.		Height of body.	Weight of brain.
			Lbs.	oz.	Inches.	Ounces.
1-2	$\scriptstyle {\left\{{\begin{matrix}\ \end{matrix}}\right.}$	Male.	14	6	28·5	33·25
		Female.	13	2	27·7	29·80
2-4	$\scriptstyle {\left\{{\begin{matrix}\ \end{matrix}}\right.}$	Male.	20	0	31·6	38·71
		Female.	18	7	31·6	34·97
4-7	$\scriptstyle {\left\{{\begin{matrix}\ \end{matrix}}\right.}$	Male.	25	8	37·5	40·23
		Female.	24	9	37·0	40·11
7-14	$\scriptstyle {\left\{{\begin{matrix}\ \end{matrix}}\right.}$	Male.	42	6	47·0	45·96
		Female.	38	6	45·0	40·78
14-20	$\scriptstyle {\left\{{\begin{matrix}\ \end{matrix}}\right.}$	Male.	68	0	60·5	48·54
		Female.	63	14	57·7	43·94
20-30	$\scriptstyle {\left\{{\begin{matrix}\ \end{matrix}}\right.}$	Male.	92	14	66·75	47·90
		Female.	86	13	62·0	43·70
30-40	$\scriptstyle {\left\{{\begin{matrix}\ \end{matrix}}\right.}$	Male.	98	3	66·5	48·20
		Female.	87	0	62·0	43·09
40-50	$\scriptstyle {\left\{{\begin{matrix}\ \end{matrix}}\right.}$	Male.	102	0	66·8	47·75
		Female.	84	9	62·0	42·81
50-60	$\scriptstyle {\left\{{\begin{matrix}\ \end{matrix}}\right.}$	Male.	102	0	66·0	47·44
		Female.	86	0	62·0	43·12
60-70	$\scriptstyle {\left\{{\begin{matrix}\ \end{matrix}}\right.}$	Male.	103	13	65·7	46·40
		Female.	86	14	61·5	42·69
70-80	$\scriptstyle {\left\{{\begin{matrix}\ \end{matrix}}\right.}$	Male.	106	13	65·7	45·50
		Female.	80	4	61·0	41·27
80-90	$\scriptstyle {\left\{{\begin{matrix}\ \end{matrix}}\right.}$	Male.	99	0	66·7	45·34
		Female.	79	0	60·0	39·77

 

The above table, made by Dr. Boyd from sixteen hundred and seven post-mortem examinations of sane persons, shows that the human brain reaches its maximum of weight in proportion to the rest of the body between the ages of fourteen and twenty in both sexes; and then it continues to decrease through life. While intelligence is rapidly increasing from twenty to sixty years of age, the brain is diminishing. The time that a man knows most is from seventy to eighty; but then