146 



D. LACY 



Fig. 4. Electron miciograpli of a small part of the highly differentiated Golgi zone of a neurone. The line A-B in 

 fig. 1 passes throughasimilar region. Magnification 21,000. 



of the cell body lying next to the nucleus. In larger 

 neurones they extend from the nucleus (which is 

 excentrically placed) into much of the cell body. 



Additional details of the structure of the Golgi 

 filaments are revealed when cells are treated by 

 Kolatchev"s method and examined by electron mi- 

 croscopy. The Golgi apparatus is found to consist of 

 chromophilic and chromophobic components as in 

 vertebrate cells (3, 6). 



Examination of neurones fixed in buffered osmic 

 acid (7) shows that the Golgi filaments are located in 

 a highly diflFerentiated zone of the cell body (fig. 4). 

 The filaments consist of paired anastomosing mem- 

 branes which enclose two substances; a dense material 

 lying within narrow folds of the membranes, and an 

 osmiophobic substance lying within small dilations 

 of the membranes (fig. 3). Lying next to the filaments 

 and scattered about much of the differentiated zone 

 are numerous small (Golgi) vesicles. Some discrete 

 Golgi vacuoles are also present. 



Comparison of material treated by Kolatchev's 

 method with that fixed in buff"ered osmic acid shows 

 that the chromophilic component of the Golgi 

 apparatus corresponds to the membranes together 

 with the dense substance they enclose. The chromo- 

 phobic component of the Golgi apparatus corre- 

 sponds to the osmiophobic substance lying within 

 dilations of the membrane. Finally the weakly 

 osmiophilic substance (seen in Kolatchev's prepara- 

 tions examined by light microscopy) arises from the 

 impregnation of the Golgi vesicles. The weakly 

 osmiophilic substance is probably the "archoplasm" 

 of previous workers (2). 



Filaments are not seen in very small neurones 

 fixed in buffered osmic acid. However, these cells 

 contain a compact organelle, lying close to the 

 nucleus, with an ultra-structure similar to that 

 described for the filaments (fig. 2). 



Kolatchev's method also reveals certain spheroidal 

 bodies. These are light to dark brown in colour and 



•#..^# 



3 





Fig. 5. Electron micrograph showing the Golgi apparatus in an epithelial cell. The apparatus is more compact than in 

 neurones but has the same basic ultra-structure (compare with fig. 3). Magnification 41,000. 



Figs. 2-5 are micrographs of tissue fixed in buffered osmic acid, pH 7.4. 



G.A. = Golgi apparatus 

 G.f. = Golgi filament 

 G.m. = Golgi membrane 



G.v. = Golgi "vacuole" (osmiophobic substance lying within 

 a dilation of the folded Golgi membrane) 



G.vs =^= Golgi vesicles 



G.Z = Golgi zone 



M = Mitochondrion 



N = Nucleus 



S.b = Spheroidal body ("lipochondrion") 



