62 LABORATORY OUTLINE OF NEUROLOGY 



the sketches. In these sketches each tract and nucleus should 

 in general be entered on one side only, so as to avoid unnec- 

 essary complexity in the finished drawings. In general the 

 ascending tracts should be entered on the right side and the 

 descending tracts on the left side. Of course, tracts which 

 decussate will appear on one side in part of the levels and on the 

 other side in other levels. 



The separate tracts and centers may well be drawn in differ- 

 ent colors of wax crayons. In the illustrations of the func- 

 tional analysis of the peripheral nerves in the literature certain 

 systems 'of nerve components are generally conventionally 

 colored, and on the basis of that usage the following color 

 scheme is suggested. For the basis of the classification em- 

 ployed, see Sections 15 to 19, 47, 52 to 57, 67, and Herrick ('18), 

 Chapters V and IX. 



General somatic afferent: 



Exteroceptiye (general cutaneous) yellow 



Proprioceptive (muscle sense, etc.) and all afferent 



cerebellar connections orange 



Special somatic afferent: 



Vestibular (special proprioceptive) brown 



Auditory (cochlear) and optic green 



General and special visceral afferent (afferent sympa- 

 thetic connections, gustatory and olfactory) red 



General visceral efferent (pre- and post-ganglionic 



sympathetic fibers) purple 



Special visceral efferent. v light blue 



Somatic efferent, including all efferent cerebellar 



tracts dark blue 



Correlation tracts black 



Do not ink the drawings at first, but indicate the outlines of 

 tracts, etc., lightly in pencil; then, when all the sections have 

 been studied as directed in Sections 63 to 101, and the neces- 

 sary corrections made, review each section and enter upon its 

 drawing any additional details desired, such as the positions 

 of gray centers, nerve-roots, correlation tracts, etc. See that 

 each drawing is fully labeled. Finally, the drawings may be 

 inked in if desired. (For another illustration of this method of 

 laboratory drawing, see Lineback, 1917.) 



Throughout the study of the microscopic cross-sections keep 

 in mind the external form of the brain in the region studied and 



