INGBERT, Dorsal Roots of Spinal Nerves. 65 
in the upper left-hand square were always counted first, then, 
in the same row, the squares to the right of this, and each suc- 
ceeding row below the first in alternate directions, so as to 
avoid confusion by passing across the fascicle from the last 
square in one row to the first in the next row. The counting 
was done by means of an automatic register, having a counting 
limit of 999, and worked by the thumb of the right hand. 
When a sub-division had been counted the number indicated 
by the register was recorded on a paper which was numbered 
and lettered to correspond to the photograph of the cross- 
section of the root counted. The sub-divisions were later 
added and the totals placed after the number of the fascicles, as 
is shown in Tables II-XX XII. 
When one sub-division was too large to be seen within one 
field of the ocular net, the method employed (except in a few 
cases where oculus 6 was used as mentioned above) was to find 
landmarks in the section and similar ones in the photograph. 
One of the limiting lines of the ocular micrometer was made to 
lie across these landmarks, which in most instances were two 
conspicuous nerve fibers; one on each side of the fascicle. This 
limiting line was so arranged as to be at right angles to one of 
the movements of the mechanical stage. After counting the 
fibers within all the squares on the side of the limiting line 
within the field of vision, the mechanical stage, carrying the 
slide with it, was moved by means of its screws, and the oppo- 
site limiting line made to run through the same landmarks, and 
the rest of the sub-division counted. In counting the cross- 
sectioned nerve fibers crossed by one of the lines of the ocular 
micrometer only those fibers the axis-cylinders of which were 
entirely within that side of the line first counted were consid- 
ered as belonging to that side, while the rest were considered as 
belonging to the other side of the line and counted 
when that side was counted. Most of the counting was done 
by daylight from a north window. Some counting, however, 
was done by the aid of an incandescent light placed two feet 
in front of the microscope. 
After counting for fifteen or thirty minutes a few minutes 
