118 HENRY O. FEISS 
ulation tests in Experiment 64 could not be said to be positive 
for the external popliteal. As to the other five dogs, the three 
which had their anterior roots fused on one side could not be said 
to show any functional gain, although two (Experiments 65 and 
70) showed some response to faradic stimulation in the roots 
below the fusion. Anatomically again, there was some regener- 
ation. 
The only animals in which functional improvement was sug- 
gested were dogs 68 and 73, both of which had paralyzed tails, 
and therefore had the fusion done so as to inelude all the roots, 
taking part in the innervation of that appendage.** In both of 
these, there also were signs of good regeneration, from the ana- 
tomical and physiological points of view. However, one could 
not be positive that the functional return of power was due to 
the fusion, because it took place so soon after. To help settle 
this point we performed similar operations in the cauda of three 
normal dogs. In these cases the tails were pretty well restored 
in power by the end of three months. It is likely that this early 
improvement 1s owing to the shortness of route between the nerve- 
collectors of the tail and the roots from which these are formed. 
As regards the whole question of the fusion of nerves, it is not 
desirable, at the present time, to discuss it further on a basis of 
the experiments above described, but, at some future time, after 
becoming acquainted with conditions of regeneration after the 
fusion of normal nerves, it is likely that these experiments will be 
alluded to again. 
In closing, I wish to acknowledge the assistance of Dr. R. H. 
Bishop in the conduct of many of the experiments, and of Dr. 
David Marine in the preparation and interpretation of anatomical 
material. I am especially indebted to Professor George N. 
Stewart, Director of the Laboratory. He has made many impor- 
tant suggestions in the plan and details of the work, as well as 
in the preparation of the manuscript. 
Cleveland, Ohio. 
94 Schiimacher: Anat. Hefte Beitrage zur Anat. und Nntwickelungsgeschichte, 
120 Heft., 1909. 
