47 



this tangle, certain nerve-fibres of the general cutaneous 

 system terminate. Such a fibre is shown in F'ig.5, g.c. f . ; its 

 arborization may be distinguished from the tangle of neurones 

 in which it lies by the somewhat greater size of its terminal 

 tw i gs . 



The neurones of the substantia gelatinosa, considered 

 morphologically, are of three varieties, all of which are rep- 

 resented in fig. 5. The one that is present in greatest num- 

 bers, giving character to the formation as such, is of quite 

 minute size, and is an extreme example of Golgi's second type 

 (Pig. 5, a. The cell-body is very small, polygonal in form, and 

 there are a few short dendrites. The axone ramifies immedi- 

 ately into an extremely complex series of branches, constitu- 

 ting the principal member of the tangle mentioned in the pre- 

 ceding paragraph. These axones are strikingly conspicuous 

 structures when successfully impregnated with chrome-silver. 



A second form of neurone is considerably larger in size, 

 its dendrites enter into the tangle referred to, instead of 

 its axone. From a polygonal cell-body, some three or four 

 dendrites radiate indifferently in all directions. The den- 

 drite is of fine calibre, and it branches repeatedly into ever 

 finer twigs. The branching of this system is far less profuse, 

 however, than that of the axone of the first variety described. 

 The difference will be readily seen by reference to F'ig.5,b. 

 The axone takes a course out of the gelatinous substance into 

 the deeper parts of the nucleus. It gives off a number of 



