G. Carl Huber 49 



vesicular variety; (3) large nuclei of the vesicular variety, often poly- 

 morphous and measuring as high as 14^^. Krause and Aguerre, in 

 another communication, describe at some length the distribution of the 

 neuroglia tissue in the human spinal cord. Attention should also be 

 drawn to the fact that these two observers have been able to stain the 

 neuroglia in apes and half-apes, after having slightly modified the 

 Weigert method. Krause has given a full account of the neuroglia in 

 the spinal cord of the ape, in which he describes small, deeply-staining 

 nuclei of neuroglia cells and larger often polymorphous, vesicular nuclei, 

 having only a small amount of chromatin. He finds the majority of the 

 neuroglia fibers fully difi'erentiated and many of them relatively thin. 

 Enrich in his last publication places himself in accord with Weigert's 

 view on the structure of the neuroglia and advances theoretical reasons 

 for accepting the same. It would lead beyond the limits of this paper 

 to do more than mention the observations of Taylor, who worked with 

 the Mallory method, and Storch and Bonome, who used the Weigert 

 method in their study of glioma and gliosis and of the behavior of the 

 neuroglia in certain pathological conditions of the central nervous 

 system of man. As pertains to the structure of the fully-developed 

 neuroglia tissue, their published results confirm in the main the views 

 expressed by Weigert and Mallory and others who have used these 

 methods. Yamagiwa has recently described a new stain for neuroglia 

 which consists of a modification of Strobe's differential axis-cylinder 

 stain. As a result of observations made with this method, he is led 

 to conclude that the neuroglia fibers are differentiated intercellular 

 structures, which are, however, not entirely or not in all instances 

 completely separated from the neuroglia cells. Mention may also be 

 made of a somewhat crude method described by Whitwell, by means 

 of which he aims to differentiate the neuroglia fibers. Sections from 

 hardened tissues are treated for a few seconds with a hot concentrated 

 solution of caustic potash, are then rinsed in water and allowed to 

 desiccate on the slide. When dry, the sections are covered with a cover 

 glass. In such preparations examined with a moderate magnification, 

 but with good illumination, a dense feltwork of fibrils may be seen. 

 Whitwell regards these fibrils as neuroglia fibers and states that " they 

 show no evidence of being direct processes of cells and do not appear 

 to branch and form a complete basket network for each element in the 

 nervous tissues, including the blood-vessels." Benda has recently 

 described a differential neuroglia stain which will be given fuller con- 

 sideration presently and will therefore receive no further mention at 

 this time. From the foregoing account it may be seen that those 



