Donatpson, Law of Innervation. 247 
All the fibers entering the leg by the crural and sciatic 
nerves are enclosed within the circle marked ‘‘Fibers entering 
the leg, 100%.’’ Atthe next lower level, the small circles 
enclose all the fibers to each of the three segments of the leg 
marked respectively : 
Thigh 46.0% 
Shank 25.3% 
Foot 28.7% 
Within the last three columns the heavy black lines indi- 
cate the splitting fibers, which according to the description in 
the text, are distributed to the the thigh, shank and foot. These 
splitting fibers are divided into two classes : 
Class a—splitting fibers, both divisions of which are dis- 
tributed to the same segment : 
Class b—splitting fibers, the divisions of which are dis- 
tributed to different segments. 
This latter class is represented by three groups: 
bi, one division of which goes to the thigh and the other 
to the foot ; 
b,, one division of which goes to the thigh and the other 
to the shank; 
bs, one division of which goes to the shank and the other 
to the foot. 
C + Si, indicates the level above the branches to the thigh; 
P + T, the level above the branches to the shank, and P1 + P2 
and T1 + T2, the level above the branches to the foot. 
Within each column is represented the several sorts of 
splitting fibers, each one bearing the designation used to indi- 
cate it in the text. The designation ‘‘a’”’ always indicates the 
splitting fibers, both divisions of which have the same distribu- 
tion. Class ‘‘b”’ is represented by the three groups, b,, one 
division of which goes to the thigh, while the other goes to 
the foot ; bs, one division of which goes to the thigh and the 
other to the shank, and finally, b;, one division of which goes 
to the shank and the other to the foot. The splitting fibers are 
counted only once, and are credited to the column in which 
they appear above C+S, in the figure. The other divisions are 
in addition to the number of fibers called for by the formula. 
