CHAPTER XXX 



CYTOLOGICAL METHODS : GOLGI BODIES * 

 MITOCHONDRIA t YOLK ETC.J 



679. In recent years some doubt has arisen as to what is the 

 Golgi apparatus. Before proceeding to a description of the various 

 methods for demonstrating this and other bodies in the cell 

 cytoplasm it will be necessary to enter into some explanations. 



What is the Golgi Apparatus ? The Golgi apparatus is 

 constituted typically in the higher vertebrate neurone by a 

 network, more or less complete, of argentophile and osmio- 

 phile substance lying in the cytoplasm. In young neurones the 

 network is situated on one side of the nucleus in the so-called 

 juxta-nuclear excentric position. In tissues which have been 

 fixed in formalin, immersed in silver nitrate solution, and then 

 reduced in hydroqviinone solution, the substance of the Golgi 

 apparatus often, but not always, becomes black with reduced 

 silver. This phenomenon can be made to occur more certainly 

 by adding arsenious acid, cobalt or uranium nitrate, or cadmium 

 chloride to the formalin fixing solution. Similarly, pieces of 

 tissue fixed in osmium tetroxide solution, and left in it for some 

 weeks at room temperature, gradually show a blackened area in 

 the same place in given cells as with the formalin silver techniques. 

 In some, but not all cells, certain vital dyes segregate in vacuoles 

 or granules in the region of the Golgi apparatus. In other words, 

 the area in which the Golgi material lies is in such cases a 

 functionally specialised part of the cell. Summarised, tests for 

 the Golgi apparatus are as follows : — (a) It goes black in the 

 formalin silver nitrate and osmic Golgi apparatus methods. 

 (b) It does not stain in neutral red.** (c) It passes centripetally and 

 is found below the fat, in ultra-centrifuged cells (§ 732). 



In metazoan cells (including sponges, Parazoa), the Golgi 

 apparatus is definitely identifiable. With the exception of the 

 Sporozoa, in the Protozoa there is still no consensus of opinion as 

 to whether true Golgi material is present. The Golgi apparatus 

 of Protozoa does not appear to us to be the neutral red staining 

 granules, though in Metazoa neutral red staining substance 



* Chondriosomes, chondriokonts, plastoehondria, " chromidia,' 

 bioblasts, chondriome, chondriomites, etc., etc. 



t Nebenkern batonettes, idiozome rods, "■ Golgi-Kopseh apparat," 

 apparato interno reticolare, dietyosomes, Binnennetz, etc. 



** See footnote § 765 ; the invertebrate dictyosome apparently does 

 sometimes stain. One, at least, authentic case is the Scorpion dictyosome. 



J By J. B. G. 296 



