568 JOHN BERRY HAYORAFT. 



judging from the drawings and preparations I have seen^ are 

 for the most part much smaller than the chromatin knobs of 

 the tortoise. 



But some authors have traced nerves into the epithelial cells 

 themselves^ where they appear to end in little knobs embedded 

 in the cell protoplasm, near but never in the nucleus. Thus 

 Pfitzner (5), working with the Amphibia, finds this to be. the 

 case; and more recently Macallum (6) describes nerves termi- 

 nating both between and within the epidermic cells of the 

 tadpole's tail. 



In the tortoise-shell the nerves certainly pass right into the 

 nuclear cavity, within which the only structures deeply stained 

 by hsematoxylin are the club- or cup-shaped masses into which 

 the nerves pass. A very remarkable fact is the ease with which 

 these preparations are obtained. I have made over twenty, and 

 in all cases good demonstrations were obtained. I have tried 

 several gold methods, but they were vastly inferior to the log- 

 wood, and, as usual, chiefly characterised by want of uniformity 

 in the results obtained. In other situations the non-medul- 

 lated nerves of the tortoise do not stain at all readily with 

 logwood. 



Papers quoted in Text. 



1. Ranvier. — ' Traite technique d'histologie,' p. 900. 



2. Klein. — ' Atlas of Histology.' 



3. Ebekth. — ' Archiv f. mikr. Auat.,' Bd. ii, p. 490, 1SG6. 



4. LEBouca. — ' Bull, de i'Acad. Hoy. de Belgique,' 1870. 



5. Peitzneb. — ' Morpli. Jalirbucb,' Bd. vii, p. 72G. 



6. Macallum, A. B. — 'Quart. Journ. Micr. Sci.,' vol. xvi. 



