148 Journal of Comparative Neurology. 



of uniform calibre was taken from the cervical region. This 

 was cut into seven nearly equal segments and immediately 

 placed in the following hardening fluids : 



(i) Sat. alcoholic solut. corrosive sublimate. 



(2) Absolute alcohol. 



(3) Alcohol 95%. 



(4) Alcohol 95%, formalin 20%, equal vols. 



(5) Formalin 20%. 



(6) Hermann's fluid. 



(7) Flemming's fluid. 



In (i), (6) and (7) the pieces remained one hour ; in the 

 others, 24. 



The pieces were properly identified and then run up into 

 paraffine and blocked, all passing through exactly the same after- 

 treatment in the same vessel, all blocked in the same block, cut 

 at the same stroke of the knife and transferred to the slide, 

 fixed (Mayer) and stained upon the slide. Thus the technique 

 in each series was uniform and similar, excepting the hardening 

 fluid used and the length of time of hardening. 



Staining was done by a variety of methods and numerous 

 modifications of the Nissl method were tried. Finally the 

 specimens were mounted in different media, on one slide five 

 specimens of Necturus cord were stained under the same con- 

 ditions and mounted in different media : Xylol Balsam, Xylol 

 Damar, Xylol Colophonium, Nissl's Benzine Colophonium, 

 Chloroform Styrax. 



The tedium of technique approaches its zenith when one 

 takes up the question of staining. An investigator may say 

 "Nissl's" method, but which one is meant? Nissl has described 

 so many that it is hard to know which is followed and although 

 the variations are slight they are of importance to the original 

 describer at least, and who should be more competent to judge? 

 Hence it may be said that in the experiments made all of Nissl's 

 methods, Rehms' modification, etc., were tried, including the 

 latest described at the time of publication. The method giving 

 apparently the most uniform and clear results, was, substantially, 

 staining in warm yi, % aq. solut. methylene blue for from 1 5 to 20 



