40 LABORATORY OUTLINE OF NEUROLOGY 



floor and cut the nerve-roots with a slender scalpel or scissors. 

 Carefully free the anterior and ventral surfaces of the olfactory 

 bulb from the lamina cribrosa of the ethmoid bone, cutting off 

 the filaments of the olfactory nerve. Cut out the hypophysis 

 from its cranial pocket in the sella turcica and leave it attached 

 to the brain by the slender infundibulum. The brain may now 

 be lifted out of the cranial cavity and preserved in formalin. 



31. As stated above, most of the dissections described in this 

 Outline can be made on either human or other brains. If brains 

 of the sheep (or dog or cat) are used, specimens and text-book 

 figures of the human brain should be kept constantly at hand 

 for comparison. A certain number of special dissections illus- 

 trating particular features should be made in advance and pre- 

 served permanently. These should -be made, if possible, on 

 human brains and should include, among others, three brains 

 sliced respectively in planes parallel with the transverse, 

 frontal, and sagittal planes of the body. Valuable demonstra- 

 tion specimens may also be made by following out the direc- 

 tions for dissecting the several fiber systems given in the 

 "optional dissections" (Sections 102-111 and 141-152), using 

 a separate brain or half brain for each system. Cunningham 

 and Waterson's Edinburgh University Stereoscopic Atlas is 

 a valuable aid in getting true pictures of the internal structures. 



If only one human brain is available for study, it is advised 

 that it be dissected as directed by Dr. Lineback ('15). By this 

 procedure the brain is first divided in the median plane into 

 right and left halves and one of these halves is then further 

 dissected by a single carefully planned incision so as to remove 

 a considerable portion of the cerebral hemisphere from the 

 brain stem and at the same time reveal the internal structure 

 of the hemisphere. The method has the further advantage 

 that the three parts into which the brain is cut can readily be 

 reassembled, so that the specimen can still be used for demon- 

 stration of the external form in its entirety. 



32. The dissection of many fiber tracts can be carried much 

 farther in well-preserved human brains than is possible in 

 brains of lower animals. Accordingly, there are included in 

 this Outline directions for a certain number of " optional dissec- 

 tions" (Sections 102-111, 141-152), for which human brains 



