Journal of 



Applied Microscopy 



and 



Laboratory Methods. 



VOLUME IV. DECEMBER, 1901. Number 12 



General Methods for the Study of the Nervous 



System. 



Biologists were accused, not so very long ago, with a tendency to neglect the 

 nervous system in their laboratory courses. Whatever may have been the reasons 

 for the existence of such a condition, it is certain that there now are means 

 whereby adequate corrective measures can be applied. The literature of 

 neurological methods has grown into bulk of indeed formidable proportions. In 

 fact, the beginner in the field of neurology is very apt to find himself bewildered 

 by the opportunities for choice between the many and widely divergent schemes 

 recommended by their enthusiastic advocates. 



This paper has been written for the purpose of describing those methods 

 which may properly claim a place in the general laboratory study of the verte- 

 brate nervous system. Since this field necessarily involves certain technical 

 difficulties, the outlines have been given some degree of detail wherever it has 

 seemed desirable to do so. The attempt has not been made to anticipate the 

 special needs of the investigator, but, rather, to serve the purposes of those who 

 desire to demonstrate, for the class room, the microscopical structure of the 

 nervous system of some vertebrate. 



1. Staining with Tro?i Hiematoxylin and Orange-G. 



While originally intended for an altogether different purpose, iron haematoxylin 

 may now be claimed as a neurological reagent of distinct value. It may be 

 applied advantageously wherever it is desired to obtain a comprehensive picture 

 of structural elements, such, e. g., as would appear in a longitudinal section of the 

 entire brain of the frog; in transverse sections through typical regions of a small 

 mammalian brain; or in sections at different levels of the spinal cord. This 

 stain exhibits the structural elements without confusing the eye with too much 

 detail, outlining groups of nerve-cells, and bringing tracts of nerve-fibres into 

 sharp relief. Its value, therefore, lies in the basis which it gives for a conception 

 of the relations between important parts of the nervous system. 



For this general purpose, the whole brain of a rat or mouse, or segments of 



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