Irving Hardesty 83 
As used by Huber, the Benda method applied to the elephant’s cord 
gave remarkably sharp contrasts. The neuroglia fibers stain a deep 
bright blue against a slightly pink but almost transparent background. 
Their contour is even and threadlike. On the other hand, white fibrous 
connective tissue, the pia mater, its ingrowths and the walls of the 
blood-vessels, stains a light brownish-red. The endoplasm (when pres- 
ent) of the neuroglia cells appears brownish-red with distinct granula- 
tions; the nerve cell-bodies and the chromatin of their nuclei, a dead 
grayish-blue; axones (axis cylinders), light brownish-red with sometimes 
a tinge of blue. The outlines of the neuroglia nuclei and their chro- 
matin masses stain a black-blue. In the various blood-vessels the blood, 
corpuscles may be noted. The red corpuscles color a greenish-blue. In 
sections prolonged in the differentiating fluids the red corpuscles be- 
come a light greenish-red or practically colorless. Of the white cor- 
puscles, the eosinophiles and polymorphonuclear types generally stain 
very dimly or not at all, while the small lymphocytes show a deep blue 
nucleus with a pinkish granular cytoplasm. The myelin portion of the 
medullary sheaths does not stain at all, but the general framework of 
the sheaths takes a light pink like the fibrille of white fibrous connective 
tissue. 
As an additional test of the selective power of the stain for neuroglia, 
the Benda method was applied to pieces of formalin-fixed lung, sali- 
vary gland, spleen and skin (human and dog). In all the steps these 
tissues were subjected to the identical procedure employed with the 
sections of the spinal cord. The result was highly satisfactory as to 
the value of the method. No blue-stained fibers were found in any 
of the sections. Both white fibrous and elastic tissue stained the same 
light brownish-red as found in the pia mater and the walls of its blood- 
vessels. In the salivary gland, for example, the white fibrous frame- 
work between the alveoli and the basement membranes about them, 
showed in beautiful detail but were stained a pale red with no trace of 
blue. The chromatin in the nuclei of the connective tissue cells stained 
blue but seldom so deeply as in those of the neuroglia cells. Some 
nuclei, however, were remarkably like certain of those found in sections 
of the spinal cord. The endoplasm about the nuclei stained the same 
color as that about neuroglia nuclei but with a much less evident granu- 
lar structure. Lymphocytes could be distinguished with their thin rim 
of granular cytoplasm. Many apparently “free nuclei” could be noted. 
As a test for neuroglia fibers the experiment indicated at least that the 
method is selective since in none of the tissues did either white fibrous 
or elastic tissue show the blue reaction. 
