72 2 HUBER. [Vol. XI. 



are seen large numbers of polynuclear leucocytes, branched 

 and spindle-shaped connective tissue cells found in a loose 

 fibrous tissue framework. By the twentieth day no trace 

 of the implanted catgut is to be seen. I must, however, 

 describe a curious appearance met with in a section of the con- 

 nective tissue uniting the central and peripheral part of the 

 resected nerve of this experiment. When such sections are 

 examined with a low power, it will be seen that in certain parts 

 the fibrous tissue is loosely interwoven, is rich in connective 

 tissue and polynuclear white blood cells, and contains here and 

 there small groups of fat cells. The portions of the section 

 having this structure are band-like in shape. Such areas are 

 from I to 2 mm. broad, and in section cut in line with the im- 

 planted catgut bundles, they now and then extend from one 

 end to the other, in a section ij^ ctm. long. Others may 

 have only one half or one quarter that length. Such areas 

 have quite straight borders ; two, three, or four may be found 

 in a longitudinal section. They are separated one from the 

 other by a narrow band of much firmer fibrous tissue. In 

 sections made at right angles to the implanted segment, six to 

 eight round or oval patches of the same loose fibrous tissue, 

 surrounded by layers of a denser connective tissue, are met 

 with. I am inclined to think that the looser connective tissue 

 supplants the implanted and absorbed catgut threads, while the 

 denser tissue was developed between the threads, its formation 

 beginning before the catgut was absorbed. 



In the above three experiments, the fibres of the peripheral 

 part of the resected nerve are found in process of degeneration. 

 In the experiments of five and ten days' duration, the periph- 

 eral portion of the nerve fibres of the central end are found 

 degenerated for a distance of about y^ ctm. ; and in the experi- 

 ment of twenty days' duration, signs of regeneration are 

 present. In longitudinal sections of this part of the nerve, 

 new axis cylinders are found in the degenerated part of the 

 central fibres, and some few in the connective tissue surround- 

 ing the resected end of the central stump. The appearance 

 presented is like that already described for sections made from 

 this region in nerves removed about twenty days after opera- 



