480 NEUROGLIA AND SENSE ORGANS. 



WEIGERT'S method (see next ), the first and, perhaps even now, most 

 important of all so-called specific processes for staining neuroglia 

 fibres. 



But the Weigert method, whilst staining neuroglia fibres and 

 nuclei of neuroglia cells intensely and, up to a point, specifically, 

 leaves the cell-bodies of the latter entirely unstained. It conse- 

 quently led to the erroneous conclusion that the processes of 

 neuroglia cells were one and the same thing as the neuroglia fibres 

 shown by the new method, and that the latter were, in the adult 

 state, only contiguous to viz., independent of the former. 



Efforts were, therefore, made to discover new methods suitable 

 for the study of neuroglia fibres and neuroglia cells and their reci- 

 procal relations. Many modifications of Weigert' s neuroglia stain, 

 the methods of BENDA, MALLORY, ANGLADE and MOREL, HELD, 

 RUBASCHKIN, DA FANO, etc., may be considered as the direct 

 outcome of such efforts. 



None of these methods, however, was sufficient to entirely solve 

 the problems resulting from Weigert 's discovery, and from the 

 comparison between the results attainable by the new neuroglia 

 stain and Golgi's process. Hence the publication of the methods 

 of RAMON Y CAJAL, ACHUCARRO, DEL RIO-HORTEGA, and the modem 

 conception that the neuroglia consists essentially of cells provided 

 with variously ramified processes (protoplasmic neuroglia), and of 

 fibres which, though a product of differentiation of the former, 

 remain, very likely, throughout life continuously connected with 

 the protoplasmic bodies and processes of neuroglia cells (fibrous 

 neuroglia). 



With all that, the very meaning of the word " neuroglia" and the 

 methods for its study are just at present the subject of fresh 

 discussions and investigations. It is, consequently, expedient to 

 fully describe in the following paragraphs only the principal methods 

 in use for the demonstration of neuroglia, taking this term to mean 

 the whole of the sustaining tissue of the central nervous organs, which 

 is plainly not connective tissue. For minute technical details and 

 methods almost exclusively used in histopathology, the original 

 papers quoted in the following paragraphs should be consulted, as 

 well as ALZHEIMER, Histol. u. Histopathol. Arb., iii, 1910, pp. 406 to 

 412 ; NISSL, Enzykl. mikr. Techn., ii, 1910, pp. 280 to 283 ; Bonome, 

 Atti R. Inst. Veneto Sc. Ixvii, 1909. 



4 



910. WEIGERT'S Neuroglia Stain (WEIGERT'S Beitr. zur Kenntniss 

 d. norm, mensch. Neuroglia, Frankfurt-a-Main, 1895 ; and the 



