556 DR JAMES W. DAWSON ON 



conditioned by the absolutely fresh state of the tissue, and it is also unsuitable for 

 tissue obtained from experimental animals. The method was not available in this 

 work, as the autopsies were made from twenty -four to forty-eight hours after death. 

 By Mallory's neuroglia method the glia fibrils are said to be brought out very 

 prominently, but in our hands it stained the tissue with such an intensity that it was 

 difficult to distinguish between glia fibrilis, axis cylinders, and connective-tissue fibres. 

 Dense glia proliferation is certainly extremely perceptible by this staining method 

 under a low magnification. 



Recent glia methods have had in view a simplification of the technique and more 

 constant results than those yielded by either Weigert's or Mallory's methods. 

 Perhaps the simplest of these are those devised by Lhermitte and Gtjccione (1910) 

 for the study of neuroglia cells and fibrils respectively. These writers claim for 

 their methods that they are available for either normal or pathological material fixed 

 within a reasonable time after death, that they are absolutely constant and specific, 

 and that the exact conditions for success in staining are easily secured. Further, on 

 account of the very exact differentiation of the tissue elements the staining allows 

 of the share taken both by the neuroglia and connective tissue in inflammation and 

 in other processes being exactly defined, and also brings into evidence the relation 

 of the neuroglia nucleus, protoplasm and fibrils to one another, thus solving the 

 much disputed question of the mode of formation of the fibrils. One great advantage 

 of both methods is that the preliminary fixative is formalin. Frozen sections are 

 taken from distilled water into an osmio-chromo-acetic mixture ; from this trans- 

 ferred to Gram's solution and then to the stain — 1 per cent. Victoria blue solution 

 for the staining of the fibrils, and phosphotungstic acid hsematoxylin for the staining 

 of the cell protoplasm. In normal longitudinal sections of the cord thus stained it 

 was possible to follow the neuroglia fibrils of the white matter as interlacing fibrils — 

 the axis cylinders being almost unstained. In areas of sclerosis also the neuroglia 

 fibril proliferation was clearly brought out, with frequently more or less altered, but 

 unstained, axis cylinders in the meshes. But in the preparations the fibrils, at first 

 stained an intense and beautiful blue, became decolorised very rapidly. Though only 

 moderately successful, therefore, with these stains, I am satisfied of their great value. 

 They are used with frozen sections : the technique, though elaborate, is much simpler 

 than that of the other methods, and the tissue need not be absolutely fresh. 



Neuroglia, if well preserved, stains with all simple methods, e.g. Van Gieson's 

 stain, and of these non-specific staining methods the most valuable were found to be 

 the Heidenhain iron-hsematoxylin and Ford-Robertson's methyl-violet stains. This 

 iron-hsematoxylin method is extremely simple and often gives very beautiful pictures 

 of the glia fibrils, nucleus, protoplasm cell bodies and processes, and their mutual 

 relations. By means of it the structure of the neuroglia cells and the mode of their 

 proliferation and hyperplasia are well brought out, and all phases in the development 

 of the glia fibrils can he followed. The methyl-violet stain is of special value in 



