THE CEREBRAL HEMISPHERES. 689 



the following parts of the encephalon as distinct ganglia : 1. The gray matter of the 

 cerebral hemispheres ; 2. The gray matter of the cerebellum ; 3. The olfactory ganglia ; 

 4. The gray matter of the corpora striata ; 5. The gray matter of the optic thalami ; 6. 

 The tubercula quadrigemina ; 7. The gray matter of the tuber annulare, or pons Varolii ; 

 8. The ganglion of the medulla oblongata. In addition, the following parts have been 

 made the subject of physiological investigation or speculation, with results more or less 



FIG. 225. Vertical section of the encephalon. (Hirschfeld.) 



1, medulla oblongata ; 2, tuber annulare; 8, cerebral peduncle; 4, cerebellum; 5, aqueduct of Sylvius ; 6, valve 

 of Vieussens; 7, tubercula quadrigemina; 8, pineal gland; 9, inferior peduncle ; 10, superior peduncle; 

 11, middle portion of the great cerebral fissure ; 12. optic thalamus ; 18, 13, gray commissure; 14. choroid 

 plexus; 15, iniundibulum ; 1(5, pituitary body; 17, tuber cineieum; 18, bulb of the fornix; 19, anterior per- 

 forated space; 2 >, root of the motor oculi communis; 21, optic nerve; 22, anterior commissure of the cerebrum; 

 23, foramen of Monro; 24, section of the fornix ; 25, septum lucidum ; 26, 27, 28, corpus callosum; 29, 80, 81, 

 82, 33, 34, convolutions and sulci of the cerebrum. The olfactory ganglia and corpora striata are not shown in 

 this section. 



definite : The peduncles of the cerebrum and of the cerebellum ; the pineal gland ; the 

 corpus callosum ; the septum lucidum ; the cerebral ventricles ; and the pituitary body. 



Weights of different Parts of the Brain and of the entire Encephalon. Most of the 

 tables of the weight of the healthy adult brain of the Caucasian, given by different ob- 

 servers, show essentially the same results, the differences amounting to only one or two 

 ounces for the entire encephalon. The average given by Quain, combining the tables 

 of Sims, Clend inning, and Reid, is 49 ounces for the male, and 44 ounces for the 

 fc-male. The number of male brains weighed was 278, and of female brains, 191. In 

 males, the minimum weight was 34 ounces, and the maximum, 65 ounces. In 170 cases 

 out of the 278, the weights ranged from 46 to 53 ounces, which may be taken as the 

 general average. In females, the minimum was 31 ounces, and the maximum, 56 ounces. 

 In 125 cases out of the 191, the weights ranged from 41 to 47 ounces. 



Quain assumes, from various researches, that, in new-born infants, the brain weighs 

 11-65 ounces, for the male, and 10 ounces, for the female. In both sexes, "the weight of 

 the brain generally 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 pro- 

 gressive diminution in weight of about one ounce during each subsequent decennial period; 

 thus confirming the opinion, that the brain diminishes in advanced life." 



The comparative weights of the several parts of the encephalon, calculated by Reid 

 from observations upon the brains of fifty-three males and thirty-four females, between 

 the ages of twenty-five and fifty-five, are as follows: 

 44 



