THE NERVOUS SYSTEM. 385 



sphere tliroughout the entire height of the thalamus, enter the latter, 

 run towards the superior surface to the superior and internal border, 

 and the pulvinar, being ultimately lost exactly in the same way as are 

 the fibres continued from the cr^ts cerebri into the corpus striatum; that 

 is, these fasciculi, the elementary fibres of which originally measure 

 0'0012-0-0025 of a line, ultimately subdivide into extremely close plex- 

 uses composed of fibres of the most extreme fineness, 0"0004-0'0008 of 

 a line, the terminations of which cannot be traced.' 



I will just notice the constitution of some structures connected with 

 the above-described ganglia. The substantia nigra of the crus cerebri 

 presents pigment-cells precisely similar to those of the substantia fer- 

 ruginea, except that they are for the most part rather smaller, and 

 have fewer processes, surrounded with nerve-fibres of the finest, and 

 also of the stronger kind. The commissura mollis contains smaller cells, 

 with 1, 2, 3, and more processes, and light-colored pigmentary contents; 

 and besides these, very many, plexiform, vertical, and horizontal, fine 

 fibres of 0-0012-0-OOlG of a line, with some still finer, less than 0-001, 

 and a few stronger measuring as much as 0'004 of a line. Tlh.Q pineal 

 gland exhibits pale, rounded cells, without any processes, and scattered 

 nerve-fibres of 0-001-0-002 of a line, and also, generally, a considerable 

 quantity of sabulous matter (brain-sand) {vid. § 118). Its peduncles, 

 their anterior prolongations, and the commissura posterior, contain fibres 

 measuring 0-001-0-003 of a line, and are composed in part also of the 

 finest fibres. The floor of the third ventricle presents, immediately 

 beneath and behind the anterior commissure, extremely large, and 

 smaller, colorless cells, with from one to four, occasionally very thick 

 processes. These are lodged in great number in a close plexus of fine 

 fibres of 0-0004-0-0012 of a line; and cells, in other respects exactly 

 similar, though not quite of the same size, also exist in the corpus mam- 

 millare, likewise intermixed Avith very numerous fibres of the finest sort; 

 there are other still smaller cells of 0-008-0-012 of a line, for the most 

 part with only two processes, in the tuber cinereum. The hypophysis 

 cerebri contains, in its anterior, reddish lobe, no nervous elements ; but 

 rather, according to Ecker (art. "Blood-vascular Glands," in Wagner, 

 " Handw. d. Physiol."), the elementary tissues of blood-vascular glands ; 

 that is to say, a vascular stroma of connective tissue, in the interstices 

 of which, lie vesicles (cells?) measuring 0-030-0'090'"'", containing 

 sometimes only nuclei, and a fine granular substance, sometimes distinct 

 cells, in older persons also colloid-like masses. The posterior, smaller 

 lobe consists of a fine granular substance, with nuclei and bloodvessels, 

 and also contains fine, varicose nerve-fibres, which, like the vessels, 

 descend from the infundibulum. 



§ 117. Uemispheres of the Cerebrum. — The white substance of the 



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