Hardest Y, Spinal Nerves of the Ftog. 75 



having a diameter of 5 micra and under were considered as small 

 fibers, and in order to have but two classes, all those above 

 5 micra were considered as large. With a combination of lenses 

 producing a magnification of 800 diameters (Zeiss-obj. 8 mm, 

 oc. 12), each division of the occular micrometer used was equiv- 

 alent to exactly 5 micra. By the aid of a mechanical stage any 

 fiber the diameter of which was questionable could be quickly 

 tested. Each section was counted by fields marked out on the 

 photograph. In case of a section containing fewer small than 

 large fibers, the section was first examined by counting the 

 small fibers. Then the large fibers were counted as a matter of 

 control. In every case, when the numbers for large and small 

 fibers were added, the sum was the same as that obtained in 

 the previous counts and recorded in Table I. 



The enumerations thus made were as follows in Table IV : 



TABLE IV. 



Table IV, containing the results of a separate enumeration of the large 

 and small fibers in the various dorsal and ventral roots indicated. In order to 

 compare the results of these counts with those previously obtained in counts of 

 the same sections and recorded in Table I, the corresponding numbers of that 

 table are placed in parallel columns. The numbers of nerve VII, indicated by 

 a star, are those found for section 2, Plate I, instead of section i, as the column 

 reads. 



While in most of the cases, the differences in the number 

 of small fibers do not accord with the differences between the 



