700 DR ROBERT KENNEDY ON THE 



fibres would, therefore, from being the most selected route, become more rapidly 

 developed, structural development thus following on functional activity. Thus in the 

 cicatrix paths of connection between corresponding nerve fibre segments would be 

 established. On such a supposition, it would be expected that the microscopic 

 appearances would be different, according as the two nerve segments were accurately 

 coapted or not, as in the former case the connecting nerve fibres might be expected to 

 follow an approximately direct course in the cicatrix, and in the latter to follow a 

 crossed course — to show, in other words, a decussation. But the microscopic ap- 

 pearances in the three cicatrices examined, as stated above, presented no very marked 

 differences, in each case showing throughout its greater part much convolution of the 

 young nerve fibres. The microscopic appearances, however, though they do not prove 

 that corresponding nerve fibre segments become connected, do not disprove it, as in 

 Exp. III. the convoluted course exhibited by the nerve fibres does not necessaril} T pre- 

 clude the possibility of the corresponding fibres connecting, although by a tortuous 

 path. It is, therefore, impossible to state from the above experiments whether or not 

 the return of co-ordinated movements was the result of the re-establishment of the old 

 paths for nervous impulses, although the histological appearances render the possibility 

 extremely doubtful. 



The restoration of function might be explained in a different way. Thus it is possible, 

 owing to the intimate admixture of the nerve fibres in the nerve stem, that, despite the 

 altered relationship of the two segments, yet fibres were brought into juxtaposition 

 which innervated muscular fibres ' in close proximity, i.e., muscular fibres belonging to 

 the same muscle or group of muscles, and that therefore the resulting inco-ordination 

 was so slight as to be without functional importance. Such a supposition would of 

 necessity leave much to the operation of chance, and would mean in a nerve like 

 the sciatic, with its extensive distribution to antergic muscles, that the functional result 

 would be the balance between the number of fibres distributed to flexor muscles and the 

 number to extensor muscles which happened to be brought into apposition. It is not 

 probable that the admixture of nerve fibres in the nerve stem, and the relationship in 

 which the two segments are placed in different cases of suture, are so uniform that this 

 balance would be identical in different cases, and consequently on such a view a differ- 

 ence of development of restoration of function would be expected, not only in different 

 cases of experiments such as I. and II., but a marked difference in development of function 

 would be expected between cases of accurate and of inaccurate coaptation. The supposi- 

 tion is therefore an unlikely one, as not only did Exp. I. and II. agree in the dates of 

 returning co-ordination and in following a practically identical course, but the same also 

 occurred as between Exp. I. and II. and Exp. III. 



The third hypothesis which may be brought forward to explain the results is, that 

 although non-corresponding segments of the nerve fibres were made to connect by the 

 mode of suturing the nerve, the nerve centres, brought by the altered paths into 

 connection with new peripheral endings, were capable of speedily altering their 



