THE MAMMALIAN NERVOUS SYSTEM 41 



well hardened in formalin are necessary. All of the dissections 

 here outlined, except a few of the " optional dissections" can be 

 made on one lateral half of a single well-preserved human brain 

 and all except the " optional dissections" can be made on the 

 brain of the sheep, though a better mastery of the subject will 

 be obtained by following this first dissection with a second 

 specimen, varying the procedure as may be necessary to bring 

 out any special features desired. If time and material permit, 

 it is recommended that one specimen (either human or sheep) 

 be dissected through as directed and the microscopic prepara- 

 tions studied, and then, with the aid of the experience thus 

 acquired, the more difficult " optional dissections" may be 

 made on a second specimen, the human brain being used in this 

 case. This Outline is prepared with this procedure in mind; 

 but it should be repeated that the directions for the use of the 

 brain of the sheep can be applied to the human brain as well, if 

 this is preferred. A very satisfactory study of the brain can be 

 made on gross material alone if microscopic sections are not 

 at hand, though a few such preparations illustrating the histo- 

 logical elements are very desirable. 



The practice at The University of Chicago, where twelve 

 weeks are allotted to the course in neurology, is to provide each 

 student with an entire sheep's brain and one lateral half of a 

 human brain taken from a dissecting-room cadaver. Through- 

 out the study of the external form of the brain both specimens 

 are kept before the student and every part studied is identified 

 on both brains and the differences noted. On this material all 

 of the dissections here outlined can be made, with the exception 

 of some of the " optional dissections," for which the cadaver 

 brains are usually not sufficiently well preserved. A limited 

 number of better preserved formalin hardened human brains 

 are set aside for the use of any students who can give the 

 necessary additional time for the optional dissections, these 

 dissections being made in a review course after the completion 

 of the other work. If, as just suggested, a second specimen of 

 the human brain is dissected, the cerebellum should not be 

 removed as directed in Section 49, thus permitting a more com- 

 plete dissection of the cerebellar peduncles (see Sections 

 103-105). This specimen, however, may be divided in the 



