'l'Ile rcliitidiis di' niitnclMiinlii.i limi otini (vtoiilasiiiic colisi H iieiits ftc. 1(7 

 Slll)Sl;illcc. ;il|(| licIwiTli llif lir|||ii|ili|i|> in the ;i\(ilH\ ( lcc;isin||;tlly. 



however, IIicn' ;ir<' imi hkhc iiiiincnius in tin- axdin' liillnck tlum clsf- 

 wliere. 'J'iipy slain nf tlic sanie cnlunr a- il(i llic niMiiiitiliril>. ( mn- 

 jiare figures ]'2 and Dì willi lirld. Isiif). |ilatc Xlll. lig. 2; and willi 

 Hatai, 1903, [date Xill, li-. 1. 



2. The Altmann metliod. — In incpaialions niadu by tiif All- 

 niann nietliod (Held, 1897. p. 22<S) 1 loiind it [»ossible to study with 

 ease very ininiitc. sliarply dtdincatcd, sti'aiiiiit oi' >lÌL;li!ly i iiiNcd, poil- 

 sliaped bodies, ab(»iit tlii'ee times as long as broad witli idimdcd ends, 

 apparently similar to those figured by Held (1897, plate XI, figures 1 

 and 2). They appear stained a unifonn bright red cnldur. sln^w wy 

 clearly between the yellowish liukes ut Nissl substance, and arc di.slri- 

 buted fairly efinall}^ thronghont the cytoplasm; but they are not so 

 numerous as the erj^throsin-stained granules mentioned al)ovc. These 

 tiny rods occur together with brown stained neurofibrils in the axone. 

 They are much less numerous, in the region of the axone hillnck. 

 than the erythrosin-stained granules; and they are arranged in a con- 

 stant fashion with their long axes parallel to the neurofibrils, whereas 

 in the remainder of the cell no definite orientation can be distin- 

 guished. Much better and more uniform preparations may be olttained 

 from this Altmann material it the sections, fixed to the slides, are 

 treated with a P/o aqueous solution of potassium permanganate for 

 about 30 sec. The peimanganate is removed by rinsing in a 5**/(, 

 aqueous solution of oxalic acid for a few seconds, and finally the 

 sections are washed in distilled water for several minutes before 

 staining (fig. 5). 



Ó'. The iroii hematvxijJ'ni method of Held. — It was naturally 

 found difficult to obtain preparations showing tlie neurosomes by the 

 modification of the iron hematoxylin method of Heidenhain advocated 

 by Held (1897 a, p. 275), because he has not given the details of it. 

 He says, however, that he obtained his best results with material 

 fixed in fresh solutions of potassium bichromate under certain condi- 

 tions which he does not specify. Spinal ganglia of the pigeon were 

 fixed in freshly prepared potassium bichromate solutions, of varying 

 strengths, for different lengths of time. The series of tissues were 



