578 ENCEPHALOX. 



A. TaUc of the Arrrage Weight of the Male and Female Brain. 



With the above results the observations of Peacock, published in the '" Monthly 

 Journ. of Med. Science " for 1847, and further observations by the same author 

 in the '• Journ. of the Pathol. Soc." in 18G0, in the main agree. 



The elaborate table compiled by Rudolph Wagner, and published in his " Vor- 

 studien zu einer wissensch. Morphol. und Physiol, des Menschl. Gehirns,' ISGO. 

 containing 964 recorded cases in which the Aveight of the brain had been ascer- 

 tained, may also be referred to as another recent useful contribution to the 

 knowledge of this subject. 



In illustration of the variation in the average weight of the brain at different 

 ages Table B. is given, deduced from the elaborate researches of Dr. Robert 

 Boyd, in the examination of the brains of 2,08G sane persons of both sexes 

 dying in the St. Marylebone Infimiary, and published in the " Philos. Trans, 

 for 1860. The weights are stated in oz. avoird. and decimal fractions of them. 



Anatomists have differed considerably in their statements as to the period at 

 which the brain attains its full size, and also as to the effect of old age iii 

 diminishing the weight of this organ. Scemmerring held that the brain reached 

 its full size as early as the third year ; the Wenzels and Sir W. Hamilton fixed 

 the period about the seventh, and Tiedemann between the seventh and eiglith 

 years. Gall and Spurzheim were of opinion that the brain continued to grow 

 until the fortieth year. The observations of Sims, Tiedemann, and Reid. 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 progressiA'e dimi- 



