No. 3-] PERIPHERAL NERVES. 717 



seen. In the other two experiments, the connective tissue 

 between the ends of the resected nerve presents a dense struc- 

 ture, not so dense, however, as the connective tissue surround- 

 ing the implanted bone tube. However, my experiments were 

 not numerous enough to admit of any full description as to the 

 nature of the absorption of the implanted bone. 



In the above three experiments, the entire peripheral por- 

 tion of the nerve operated upon was found in process of 

 degeneration, the extent of which was proportional to the time 

 intervening between the resection of the nerve and death of 

 the animal. The peripheral end of the central segment was 

 degenerated to the extent of i ctm., while central-ward it pre- 

 sents a normal appearance. In the experiment of twenty days' 

 duration, regeneration had begun in the peripheral end of the 

 central stump. Longitudinal sections through the central 

 wound in this experiment, stained in anilin blue and safranin, 

 simulate very closely the appearances presented by a section 

 through the central wound twenty-one days after the implanta- 

 tion of a nerve segment, which has been previously described 

 and diagrammed in PI. XXXIV, Fig. 6. In the undegenerated 

 part of the fibres of the central end, the axis cylinder presents 

 a normal appearance ; it often ends distally in a small bulbous 

 enlargement, from which or from the axis cylinders just above, 

 can be traced, for a shorter or longer distance, fine threads 

 stained deeply with the anilin blue (the new axis cylinders) 

 into the degenerated portion of the central fibre. Some few 

 of the axis cylinders of the central end show the branching 

 diagrammed in PI. XXXV, Fig. 12. In the connective tissue 

 below the central stump no axis cylinders were met with. 



In the experiment of fifty-four days' duration (No. 30) the 

 connective tissue between the outer and inner ham-string 

 muscles, which surrounded and united the central and periph- 

 eral ends of the resected sciatic, was removed, and to the 

 eye no trace of the bone tube was visible. In longitudinal 

 section of the peripheral end of the central stump of the sciatic 

 and the connective tissue just below, the following observations 

 are to be made : The sciatic is seen to end in a large bulb 

 nearly a ctm. in diameter, and is surrounded by a dense con- 



