726 HUBER. [Vol. XI. 



{d) L^tUvant' s Flap Operation. 



L^tievant's flap operation was performed seven times 

 (Exps. 42-48). Physiological examination of the nerves in- 

 volved showed the peripheral segment of the resected nerve to 

 be degenerated in every case. Microscopical examination results 

 as follows : In the experiments of five (Nos. 42 and 43) and 

 ten days' (Nos. 44 and 45) duration, the nerve fibres of the flap 

 made from the central stump, as also the fibres of the periph- 

 eral part of the resected ulnar, are found to be in process of 

 degeneration. In longitudinal and cross-sections of these por- 

 tions of the nerves involved in the above experiments, only 

 fibres presenting a fragmented myelin, and containing an 

 hypertrophied protoplasm in which are to be found an increased 

 number of the nuclei of the sheath of Schwann, are met with. 

 The rapidity of the breaking up and absorption of the myelin 

 is about the same in the nerve fibres found in the flap as for 

 the fibres found in the peripheral part of the resected nerve, 

 differing in this respect from an implanted segment, the fibres 

 of which undergo degeneration much more speedily than do 

 the fibres of the peripheral part of the nerve to which the 

 implanted segment is sutured. Why this should be so is 

 somewhat difficult to explain. The only explanation which I 

 should care to suggest is to be found in the organic union 

 between the flap and the peripheral end of the part of the 

 nerve from which it was made, through which the passage of 

 lymph and blood currents may be maintained. The more 

 favorable nutrition thus afforded may to some extent retard the 

 degeneration. Between the degenerated fibres of the flap are 

 found a large number of polynuclear leucocytes. Between the 

 peripheral end of the flap and the distal ulnar segment the 

 presence of wandering cells and embryonic connective tissue 

 cells, of branched or spindle shape, is to be noted. 



It will be remembered that in making the flap a thin knife 

 was pushed through the nerve trunk about Y^ ctm. from its 

 end, and without withdrawing the blade the nerve trunk 

 was divided into two parts to the extent desired. In that part 

 of the central stump from which the flap was cut many fibres 



