THE MAMMALIAN NERVOUS SYSTEM 41 



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 

 Anatomie, Leipzig, 1905, and a more complete list in Eycles- 

 hymer's work ('17) already cited. 



35. Suggestions regarding dissection methods. — The study of 

 the internal structure of the brain may be made either by tearing 

 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-pre- 

 pared gross sections (cf. Barker and Kyes, '00), but the inter- 

 pretation 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 through the 

 medulla oblongata and pons. At least six levels of the medulla 

 oblongata should be studied, and more if possible. Similar 



