THE MAMMALIAN NERVOUS SYSTEM 43 



sistently. Accordingly, the student must be familiar with some 

 other of the more commonly used names also. The SNA 

 terms or their English equivalents are used in this Outline, save 

 that dorsal and ventral are substituted for posterior and 

 anterior and that some fiber tracts (notably in the spinal cord) 

 are given names of clearer physiological significance. A list of 

 synonyms of anatomical terms is appended to W. Krause's 

 Handbuch der Anatomic, Leipzig, 1905, and a more complete 

 list in Eycleshymer's work ('17) already cited. 



35. Suggestions regarding dissection methods. The study of 

 the internal structure of the brain may be made either by tear- 

 ing or teasing with blunt instruments, or by making series of 

 gross and microscopic sections through the brain in various 

 planes. A surprisingly large amount of detail can be seen in 

 well-prepared gross sections (cf. Barker and Kyes, '00), but the 

 interpretation of this detail is very difficult unless the complex 

 form relations of the parts have been previously determined by 

 other methods of dissection. The gross and microscopic struc- 

 ture of the brain should be correlated so far as possible from 

 the start, and an effort should be made to form some idea, even 

 though imperfect, of the functional significance of every part 

 as soon as it is observed. 



Great care must be used in brain dissection. Do not begin the 

 dissection until, by the study of the surface anatomy and of 

 figures in text-books and atlases, as well as by reading, you 

 have a clear idea of the relative positions and connections of the 

 deep structures to be dissected. Sharp instruments, such as 

 scalpels and scissors, should be used only when indicated in the 

 directions. Avoid as far as possible the contact of metal with 

 the brain tissue. For teasing, use a sharpened orange-wood or 

 bone manicure stick. Tracts should be dissected out in the 

 direction in which the fibers run, since teasing at right angles 

 breaks the fibers, thus making it impossible to confirm their 

 course, and finally produces an untidy dissection. 



36. Parallel with the examination of the gross anatomy of 

 each part of the brain, microscopic sections should be studied 

 illustrating its histological structure. These sections should 

 include transverse sections through the spinal cord at four 

 levels (cervical, thoracic, lumbar, and sacral) and a series 



