Literary Notices. xxxi 



der consideration are to be regarded as identical with the spider cells 

 (astrocytes) seen in Golgi preparations of the neurogha. '1 he spider 

 cells described by these observers are said to be scantily distributed in 

 normal nerves. They are more numerous in regenerating nerves, 

 especially toward the end of the third or fourth week. The processes 

 of these cells are said to run longitudinally and are more numerous and 

 larger in the distal than in the proximal segment and in the intermediate 

 scar tissue the spider cells form an interlacing network. The processes 

 of these cells do not anastomose at this stage in the regeneration of the 

 nerve, though they often overlap. If the reviewer is correct in his in- 

 terpretation of the account and figures given by Ballance and Stew- 

 art, the spider cells described by them are to be regarded as the cells 

 from which the new axis cylinders develop. 



In experiments numbering from 42 to 84, the nerve tissues were 

 stained by Stroebe's method for axis-cylinder differentiation. The ob- 

 servations on these preparations corroborate in the main those made on 

 preparations stained after Weigert's differential myelin staining method. 

 Small groups of axis cylinders, stained blue, are seen m the proximal 

 end, "at a considerable distance below the most oudying extremities of 

 the unbroken axis cylinders," by the end of rhe second week after sec- 

 tion. These small bundles or colonies of axis cylinders are said to be 

 found independently of the central axis cylinders. In the distal seg- 

 ment, the regeneration begins somewhat later, also developing, how- 

 ever, as separate threads alongside the elongated nuclei of the neuri- 

 lemma. 



"The new axis cylinders increase steadily in length and in diam- 

 eter. Their imbricated ends fuse together and at the end of eight 

 weeks, they form long, blue, beaded lines, whose central ends are con- 

 tinuous with the axis cylinders of the proximal segment." These ap- 

 pearances obtain in the distal segment of a divided but sutured nerve. 

 Young axis cylinders were, however, also seen in distal segments not 

 united to the central segments, by the end of the fourth week. These 

 new axis cylinders do not, in unsutured nerves, attain their full matur- 

 ity; "they show a smaller diameter and are more beaded and sinuous." 



In experiments numbering from 86 to 138, the nerve tissues were 

 stained mosdy by Van Gieson's method, and consideration is given 

 especially to the cellular elements. We shall here, however, consider 

 only their observations on the behavior of the neurilemma nuclei. 

 These nuclei are distinguished from the connective tissue cell nuclei by 

 having an oval shape, while the latter are rod shaped. The neurilemma 

 nuclei begin to proliferate in the distal segment by the end of the sec- 



