Beambei.l & GATEtiBY—Golffi Elements of Mammalian Nerve Cell. 277 



In material fixed in Champy-Kull, Flemming-without-acetic-aeid, Petrunkewitseh, 

 10 per cent, ibnnahn, or 90 per cent, alcohol, the Golgi rods appear as unstained 

 ghosts. On account of the highly granular nature of the cytoplasm, it is 

 impossible m the living cell, to identify the Golgi rods with certainty, but highly 

 refractive bodies, which are probably they, and resemble the nebenkern batonettes 

 of the living spermatocyte, can sometimes be distinguished. Attempts were 

 made by eentrifugmg the ganglia in their own lymph, to segregate the various 

 cytoplasmic inclusions into distinct regions of the cell. It was hoped that by 

 this method the Golgi rods could be made to occupy a definite region, and could 

 m consequence, be more easily identified "intra vitam." The apparatus' 

 however, remained scattered around the nucleus in Da Fano preparations, Avhich 

 had been fixed immediately after centrifuging for half an hour at 4,000 revolu- 

 tions per minute, occupying exactly the same position as in the normal cell.^ 



V. — The Mitochoistdria. 



The mitochondria appear as numerous minute golden specks scattered through 

 the cytoplasm after the silver methods of Da Fano and Cajal. They appear 

 brown in Mann-Kopsch preparations, and dark grey in material fixed in Champy- 

 Kuil or Flemming-without-acetic-acid, and stained in iron-hfematoxylin. The 

 mitochondria are therefore not unique, but closely resemble those, described from 

 the ganglion cells of many vertebrates (Cowdry). 



VI. — The Nissl and other Granules. 



In order to see if the tigroid substance could be identified in the neurones 

 of Helix, some material fixed in Petrunkewitsch, and stained by Scott's 

 hffimatoxylin-eosin method (see Bolles Lee, 1922), or in toluidine blue, was studied. 

 No marked granulation was present, but in all the cells fine floeculent granules, 

 taking the blue stain deeply in each case, were scattered all through the cytoplasm 

 of the cell body, and were in places more definite and better developed. It is 

 probable that these basophil granules do represent the tigroid body of the 

 neurones of vertebrates. 



In the live cell a number of granules of uniform size are easily seen (fig. 7). 

 They are scattered through the cytoplasm, but may be more or less aggregated 

 in places. These granules are present in every neurone, and appear to be a 

 definite constituent of these cells. They have a strong affinity for Soudan III, 

 and also take Janus green and Neutral red. They do not stain perceptibly in 

 Bismark brown. Dahlia, or 1 per cent, osmic acid. They do not appear after 

 fixation in Da Fano's, Cajal 's, Maitn-Kopsch 's, or PetiTinkewitsch 's fluids, or in 

 90 per cent, alcohol, or 10 per cent, formalin. They are preserved in Champy- 

 KuU's fixation or Flemming's fluid without acetic acid, and stain well if these 

 methods are followed by the iron-haamatoxyliii technique (fig. 6). They take the 

 Fuchsin strongly after Champy-Kull staining. On centrifuging they collect at 

 the top of the cell. It is difficult to state the nature of these granules from the 

 above results; they are possibly lecithin or an allied substance. 



VII. — Argentophil Zones. 



A dark perinuclear zone is present in many of the neurones of Helix prepared 

 by the silver methods of Da Fano and Cajal. This zone is approximately 

 coincident with the distribution of the Golgi rods, and is narrower and less dense 



^We would like to take tliis opportimity of thanking Professor H. H. Dixon, of Trinity 

 College, for his kindness in allowdng us to use the centrifuge in the School of Botany. 



