572 ANNALS NEW YORK ACADEMY OF SCIENCES 



ing down the cervical sympathetic trunk. Simpson and Young^ showed 

 the importance of these peripheral connections by cutting a regener- 

 ating nerve peripheral to the original suture, which prevented the re- 

 establishment of peripheral connections. Weiss and Taylor^ also 

 found evidence that fibers were smaller when re-innervation of the end 

 organs was prevented. 



SUMMARY 



1. Excised, distal stumps of tibial, peroneal, and saphenous nerves of 

 cats were studied oscillographically and microscopically, at intervals, 

 up to 1363 days after transection and suture. 



2. The processes of maturation or reconstitution of fiber diameter 

 and impulse conduction velocity continued over a long period of at 

 least 544 days. The regenerating fibers never completely recovered. 



3. Crushed nerves recovered fiber diameter and conduction velocity 

 more rapidly than sutured nerves. 



4. Delay between transection and suture of more than 6 months in- 

 terfered with the reconstitution of the regenerating fibers. 



5. Cross-suturing a nerve containing large fibers into a distal stump 

 containing small connective tissue or Schwann tubes resulted in re- 

 striction of fiber diameter growth. 



REFERENCES 



1. Gutmann, E., & F. K. Sanders 



1943. J. Physiol. 101:489. 



2. Weiss P. 



1944. ' J. Nemo.surg. 1: 400. 



3. Holmes, W., & J. Z. Young 



1942. J. Anat. 77: 63. 



4. Simpson, S. A., & J. Z. Young 



1945. J. Anat. 79:48. 



5. Gasser, H. S., & H. Grundfest 

 1939. Am. J. Physiol. 127: 393. 



6. Hammond, W. S., & J. C, Hinsey 

 194.'). J. Comp. Neurol. 83: 79. 



7. Berry, C. M., H. Grundfest, & J. C. Hinsey 

 1944. J. Neurophysiol. 7: 103. 



8. Sanders, E. K,, & J. Z. Young 

 1944. J. Physiol. 103: 119. 



9. Weiss, P., & A. C. Taylor 



1944. J. exp. Zool. 95:233. 



