5,3S TIIK RABTiTT chap. 



ami is L'xtcnsinns inlo the frontal, paricia], and Icnipnral lolies. 

 Note : — 



J. The ht'/'pOLa/it/'iis, the ror/^us sirialiini, tlio cJioroid pltwus^ and 

 the SL-ptinii. liaiduiit (\>. 514). Tlicn cut away the rest uf the same 

 hemispliere ::,(» as to expose — 



2. a, Tlie (Uenci'phalon and its (wo lateral halves (optic thalanii) 

 between which the ihinl -viilriik is enclosed ; from its roof the stalk 

 of the pineal body arises ; /', the two pairs of optic iohcs. Cut away the 

 lateral half of the cerebellum of the same side, and note — 



3. The I'a/ve of I'ia/ssci/s, the foiiytli ventricle, and the tree-like 

 appearance (aiiwr vitic) of the cerebellum in section. 



III. Now reduce the whole brain to a longitudinal vertical section 

 (Fig. 132), cutting it through with a sharp knife very slightly to that 

 side of the median line which )'oii have already dissected, so as to 

 expose the median ventricles in section. Make out, on the uninjured 

 half, the relations of the t/iin/ ventricle, iter, fonrlli ventricle, foramen 

 oj Monro, infnndibnluin , optic chiasHia, corpus callosnm and fornix, 

 lamina tenninalis, anterior, middle, and posterior commissure, crura 

 cerebri, valve of I'ieusscns, pons Varolii, i~c. Sketch. 



I\'. :\ series of thick transverse sections should be made through 

 another thoroughly hardened brain, and the relations of the parts 

 already seen by dissection examined. 



II. The Eye. 



On account of its larger size, it is better to .substitute the eye of an ox 

 or sheep — which can be obtained fresh from a butcher — for that of the 

 r.alibil. Two specimens should be obtained, and the fat, muscles, 

 an<.l any portions of the e)'elids remaining attached cleared awa)'. 

 I. .\fter noting the conjuncti-i'a, cornea, sclerotic, optic nerve, iris, and 

 pupil, insert the scissors into the margin of the cornea and cut round 

 and remove it, so as to expose \\\t aqueous chamber, noting the aqueous 

 humour, as well as ihc iris, Icm, and ////// (compare Fig. 57). 

 Sketch. 



Insert the handle of a scalpel Ijctween the iris and sclerotic and 

 separate off the latter from the choroid around the outer half of the eye- 

 ball, first making four radial cuts in the sclerotic, beginning at its 

 margin, at equal distances from one another. Turn back the four flaps 

 thus made, and insert pins through them so as to fix [the eye firmly 

 ■ low n under water with the iris uppermost : note the ciliary muscle around 



