240 R. L. KITCHELL 



center of each etched circle of the Plexiglass gauge. The needle actuated a 

 mechanical counter. After all the fibers in the photograph of the same size 

 or smaller than the smallest circle were marked and counted, the number 

 was recorded and the next circle on the gauge was used in a similar manner. 

 In fasciculated nerves, the data was recorded for each fasciculus. 



/ / 



/ 



Fig. 5. Photograph illustrating method of counting fibers and determining 

 their diameter. The circles of the gauge are outlined in black for illustrating 

 only. The mechanical counter is held in the right hand. The pointed tip of 

 the counter is inserted through the small hole in the center of each circle and 

 into the photographed enlargement of a fiber of corresponding diameter; thus 

 sizing, marking and counting is accomplished. 



As a control, direct measurements of the diameters of selected and 

 identifiable fibers were made from the microscopic sections using a cali- 

 brated ocular micrometer and the high power of a microscope. These 

 measurements were made by a skilled technician without knowledge of the 

 results obtained by the photographic procedure described above. These 

 control measurements revealed no significant diff'erences between the two 

 methods of measurement. 



The chorda tympani nerves of dogs and cats were not fasciculated 

 whereas those of the other domestic animals were fasciculated (Figs. 6, 7, 

 and 8). The number of fascicules present in different cross-sections of the 

 nerve varied (Fig. 8). Anastomoses between fasciculi occurred at irregular 

 intervals. The appearance of a perineural trabeculus indicated the for- 

 mation of a new fasciculus or an anastomoses between two fasciculi. The 

 chorda tympani nerves in some sections in the pig were observed to be 



