Ranson, AUcraiions in Spinal Ganglion Cells. 129 



I 

 classification, however valuable it iiiaj be as an aid to description, 



must be more or less artificial. 



A simjDler classification has been given by Cox ('98) who makes 

 size the basis of differentiation; the large and the small cells form 

 his two main groups. The large cells fall into two types. The cells 

 of Type I present granules of irregular size and shape, which only 

 in the periphery of the cell have an elongated form. There is no 

 concentric arrangement of the granules, and the nuclei are approx- 

 imately centric. Type II comprises cells with large elongated 

 granules which have a tendency to arrange themselves in rows. The 

 nucleus is excentric. The small cells resemble, so far as the character 

 of their chromatic substance is concerned, the large cells of Type I. 

 Hatai (1901) has also emphasized the importance of size as a basis 

 of classification of the spinal ganglion cells. 



Warrington and Griffith ('04) have adopted a classification which 

 is, in the main, very satisfactory and which really dift'ers but little 

 from that of Cox. These authors merge Lugaro's Types T and II 

 into one and call them the "clear cells." These correspond to Cox's 

 large cells of Type I. Lugaro's Type III is accepted and comprises 

 the "obscure cells." These correspond to Cox's small cells. Lugaro's 

 Type IV is divided into two groups. The larger ones, which are 

 all of medium diameter, are called the "coarsely granular cells" and 

 correspond in all probability to Cox's large cells of Type II. The 

 small cells of Lugaro's Type IV are called the "smallest clear cells." 

 They are rare, but differ markedly from the other small cells in 

 that the protoplasm is not diffusely colored. These cells are not 

 given a place in Cox's classification. 



According to Warrington and Griffith, the large, clear cells rep- 

 resent about 25 per cent of the total number; they vary in size from 

 35 to 100 microns. The coarsely granular cells are much less numer- 

 ous, re])resenting about 4 per cent ; they are of a rather uniform di- 

 ameter of 35 to 50 microns. The obscure cells varying in size from 

 10 to 5(5 microns constitute G8 per cent or about two-thirds of all of 

 the cells. In the following table are given the size and relative num- 

 ber of the various types of cells as Warrington and Griffith found 

 them in the second cervical ganglion of the cat. The corresponding 

 types in the classification of Lugaro and Cox are also indicated. 



