Ranson, spinal Nerves, 103 



but also by the fact that they stain more intensely with the diffuse 

 protoplasmic dyes. Among those who have confirmed these 

 observations of v. Lenhossek may be mentioned Flemming 

 ('95) and Cox ('98). These small cells correspond to Lugaro's 

 Type III and Hatai's Type II. 



In connection with another investigation the writer has obtained 

 preparations of the spinal ganglion by a slight modification of 

 DoNAGGio's Method VIP (Donaggio '04) which demonstrate 

 in a very striking manner a difference, probably chemical but 

 possibly structural, between the large and the small cells. Since 

 no other method presents so marked a contrast between the two 

 cell types it is worth while to note the peculiarities of these 

 preparations (see Fig. i). The large cells present an absolutely 

 colorless cytoplasm, throughout which there is a network of deep 

 blue threads. These are largely absent from the nucleus. The 

 small cells, on the contrary, present a cytoplasm of a deep violet 

 which is almost entirely free from the blue threads, while the 

 nucleus contains them in abundance. These same threads are 

 seen in the axis cylinders. After a careful study of the literature 

 it has not been possible to identify these threads with any known 

 structure; but since the granular reticulum of Cajal, the Nissl- 

 bodies, the GoLGi-intracellular-net, the canals of Holmgren, 

 the neurofibrils of Bethe and the still different fibrils of Donaggio 

 and Cajal together with the remaining protoplasm and the nu- 

 cleus must occupy nearly all the space in one small cell, it does not 

 seem probable that the threads just described are new structures. 

 There can be no question however concerning the clear distinc- 

 tion which these preparations show between the large and the 

 small cells, since the difference is a constant one and the picture 

 is always the same. The distinction so strongly emphasized in 

 these preparations is probably a chemical one and has its counter- 

 part in the functional differences about to be mentioned. It 

 should be noticed that there is a certain number of transitional 

 cells which partake of the qualities of both large and small cells 

 and are usually of medium size. Several are represented in the 



' DoNAGGio's Alethod VII (modified). — Pieces 2 to 3 mm. in thickness are fixed for 24 hours in a 

 saturated solution of mercuric chloride in 10 per cent formalin to which has been added i per cent of 

 glacial acetic acid; iodine-water 24 hours; distilled water 2 hours; pyridine 48 hours (change once); 

 distilled water 24 hours; ammonium molybdate 24 hours; distilled water i hour; pyridine 48 hours 

 (change once); an aqueous solution of thionin y-j^o y, prepared at least two weeks previously (change 

 once and stain for 48 hours); dehydrate and embed in paraffine; cut sections 5 to JH thick. 



