REGENERATION OF PERIPHERAL NERVES 483 



crushing. Sections of the left side have been designated as left 

 or control. 



Only such cases as presented proximal, distal and control sec- 

 tions suitable for photographing and counting were selected. 



The photographs were made with a Zeiss 8 mm. apochromatic 

 objective and a no. 4 apochromatic eyepiece. Hardesty's ('99) 

 method of counting fibers was employed. This consists in re- 

 cording each fiber automatically by pricking a hole in each fiber 

 image of a photographic print. The original specimen is ob- 

 served under the microscope during the process. The counting 

 was done with a Zeiss 2 mm. immersion objective, a no. 4 eye- 

 piece and a draw tube of 160 mm. All counts and measurements 

 were made with the same optical combination. 



EFFECT OF OPERATION 



In order to understand the effects of destroying the continuity 

 of the peroneal nerve, it should be borne in mind that the fibers 

 of this nerve are supplied to the following muscles: the peroneus 

 longus, which passes around the external maleolus across the 

 plantar surface of the foot and is inserted into the base of the 

 first metatarsal — its action is to extend and slightly rotate the 

 foot outward; the peroneus brevis, which passes around the 

 external maleolus and is inserted into the base of the fifth meta- 

 tarsal — its action is to abduct and to extend the foot; the P. 

 tertius and quadratus fused with the extensor longus digitorum 

 — their action is to extend the toes; and the tibialis anterior 

 which is inserted into the base of the first metatarsal; its action 

 is to extend the foot at the ankle and rotate the foot inward. 



The inmiediate effect of the operation was in every case to 

 cause a paralysis which resulted in a flexion of the toes and a 

 rotation of the foot inward. Since no fibers of the peroneal are 

 distributed to the gastrocnemius muscle and plantar muscle, it 

 may be assumed that the deformity immediately following the 

 operation is due to the action of these muscles. This deformity 

 in many cases rapidly disappeared and in most cases after the 

 lapse of six to ten days it was difficult to detect any abnormality 

 in the movements of the animal. 



