Hatai, Origin of New-oglia. 293 



3. Staining characters. The manner of staining is more 

 important for a distinction of the two types. Type "a" stains 

 very faintly with the eosin, while the type "b" shows stronger 

 affinity for this reagent. The difference in staining between 

 the two forms is quite evident in both the white rat and mouse. 



Some of the previous investigators (Weigert, Mallory, 

 Huber) who examined the neuroglia tissue, noticed two vari- 

 eties of nuclei, one staining more deeply than the other. It is 

 however not easy to identify either of their forms with those 

 here described. 



4. Internal structure of the nuclei. This is the most im- 

 portant feature for the classification of the nuclei into two types. 

 In type "a," the nucleolus is always distinctly visible lying in 

 or near the center of the nucleus. It takes a basic stain like 

 the nucleolus of the nerve cells. The acidophile particles which 

 hang on the filaments of the linin reticulum are less numerous 

 than in the case of type "b." The arrangement or distribution 

 of the acidophile particles, as well as the distinct formation of 

 a linin network, is exactly similar to that of the nerve cells 

 (Fig. 9). The latter (type b) however, presents just the oppo- 

 site characters to type "a." As a rule the nucleolus and linin 

 network are not visible. Exceptional cases where the nucleoli 

 and linin substance were present in type "b, " have been ob- 

 served several times. In these cases, however, the reticular 

 formation is peculiar to this type, and entirely different from 

 that in type "a." Further, the large number of the acidophile 

 particles aggregated along the periphery of the nuclei indicates 

 plainly that these peculiar nuclei are merely a modification of 

 the type "b." The size of the acidophile particles in type "b" 

 is variable, some of them being very large. These large par- 

 ticles — the nucleoli — are probably due to the fusion of several 

 smaller particles. 



From the above description it is concluded that in the 

 developing nervous system of these animals, the neuroglia 

 nuclei may be divided into two types according to their form, 

 staining characters and internal structure. 



_ The question arises at once concerning the origin of the 



