cxxxvi Journal of Comparative Neurology. 



out the peripheral portion. Earlier writers suppose that the axis cylin- 

 der remains intact. Neumann and Eichhorst believe that it suffers trans- 

 formation without actually disappearing, but most writers describe its 

 disappearance with the sheath structures. The belief that a nerve fibre 

 is an outgrowth of a cell in the central system (often several feet long!) 

 has contributed to produce a predisposition to a belief in the degenera- 

 tion as a result of trophic disturbance. Cireat difference of opinion 

 exists as to the possibility of a union by first intention. .Some cases in 

 which, after suturing a nerve, there was almost immediate restoration of 

 function seem to sustain such a view. 



The paper above noticed coatains abundant historical matter and a 

 full list of titles. The work of the authors themselves has been largely 

 experimental, but in all cases the results have been elaborately checked 

 and enlarged by histological investigation, thus giving to the results ob- 

 tained a degree of precision which cannot be too highly commended. 

 Dogs were used in the experiments and the ulnar, or ulnar and median 

 nerves were selected. Operations were carried on witii antiseptic pre- 

 cautions and the nerve fibres were sutured with carbolized catgut or cat- 

 gut in juniper oil. Two sutures were used, one on each side, the needle 

 being passed through the epineurium. Continuity of the nerve wa^ de- 

 stroyed by section with sharp scissors, crushing by a ligature, or coagula- 

 tion by means of a current of water at 8o degrees C. passing through a 

 curved glass tube. Morphia and ether were employed as anaesthetics. 

 The testing stimulus was a unipolar electric current, the indifferent elec- 

 trode being applied oyer the skin of the sternum. In some cases a small 

 block of hard rubber was passed under the nerve and a direct impact 

 employed as stimulant. 



1. In none of the cases was there union by first intention, the per- 

 ipheral end degenerating throughout its whole extent. 



2. The time necessary before loss of irritabilit)' and conducting ap- 

 |)cars, varies greatly (between 2 and 4 days.) 



3. The return of function^-eadily but gradually takes place if the 

 ends are primarily sutured. 



4. The irritability returns first in the vicinity of the wound. Tt 

 only returns when regeneration has proceeded so far that some medul- 

 lated fibres are present. 



5. The return of functioii takes place more quickly in sensory than 

 in motor fibres. This is explained by the authnrs as due to the greater 



