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. 215. Vertical section of the encephalon. (Hirschfeld.) 



1, medulla oblongata ; 2, tuber annulare; 3, 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; 13, 13, gray commissure; 14, choroid 

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

 forated space; 20, root of the motor oculi coinmunis; 21, optic nerve; 22, anterior commissure of the cerebtum; 

 23, foramen of Monro ; 24, section of the fornix ; 25, septum lucidum ; 26, 27, 28, corpus callosum ; 29, 30, 31, 

 32, 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. 

 We have, however, little if any positive information concerning these parts, except as 

 regards their general anatomical relations ; and their physiology really amounts to little 

 more than a history of the vague speculations of the ancients or the fruitless experiments 

 of modern observers. It is to be hoped that future anatomical investigations, chiefly in 

 following out the course of the fibres of the encephalon and their connections with the 

 cells of the different collections of gray matter, will throw light upon the functions of this 

 part of the cerebro-spinal axis ; but, at present, all physiologists will admit that we have 

 received very little aid from this source. In our anatomical descriptions, therefore, we 

 shall confine ourselves to those points that are strictly physiological. 



Weight 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 is 49 ounces, avoirdu- 

 pois, for the male, and 44 ounces for the female. This is the general result obtained by 

 combining the tables published by Sims, Clendinning, Tiedemann, and Reid. The num- 

 ber 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 

 weight 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 weight ranged from 41 to 47 ounces. 

 44 



