298 GOLGI BODIES ETC. 



inclusions, do not stain in neutral red (except in the lethal stage), 

 and especially in vertebrate cells stain specifically in Janus Green. 

 In the male metazoan germ cells, the mitochondria form the 

 middle-piece, the Golgi bodies secrete the acrosome. The only 

 exception to this is in the sperms of Peripatus where the mito- 

 chondria only doubtfully form a small middle-piece. Here, 

 however, the acrosome is formed normally from a Golgi body. 

 In seeking a discrimination between Golgi bodies and mitochondria 

 it is useful to make slides of the germ cells, and necessary to use 

 the ultra-centrifuge where doubt may arise. 



682. The Validity of Preparations showing Golgi Bodies and 

 Mitochondria. Preparations which show Golgi bodies and 

 mitochondria are regarded as valid for the following reasons : — 

 {o) The stained preparations correspond in every way with living 

 cells in which these cytoplasmic inclusions may be seen, e.g. 

 testicular cells of insects such as Gryllus and Lepisma, or of 

 molluscs such as Helix aspersa. (b) The cell inclusions undergo 

 definite and fixed movements in secretion {e.g. pancreas, thyroid), in 

 spermatogenesis, and in mitosis of the cell, (c) The cell inclusions 

 may be centrifuged into layers by the ultra-centrifuge of Beams. 



683. Study of Golgi Bodies and Mitochondria, Vitally. This 

 may best be carried out in molluscs such as Helix aspersa or 

 insects such as Gryllus or Lepisma, in which both types of in- 

 clusions are to be seen supra vitam in the spermatogenic cells 

 especially. The requisite organ should be dissected out in appro- 

 priate salt solution (§ 1430) and after teasing, if necessary, 

 mounted in a hanging drop preparation. (See Gatenby, Proc. 

 Royal Society of London, Vol. 104B, 1928 ; R. N. Mukerji, 

 Jour. Royal Microscopical Society, Vol. 49, 1929 ; and H. Herbert 

 Johnson, Zeit.fur wiss. Zool., Vol. 140, 1931.) 



The appearance of living cells may be compared with the 

 images got with Weigl, Kolatchew and Flemming-without-acetic 

 acid, or Champy iron-alum hjcmatoxylin slides. In vertebrate 

 cells it is less easy to identify these inclusions in the living cell, 

 but the regions which impregnate or stain with the methods 

 described in this chapter may be ultra-centrifuged into distinct 

 layers. For the ultra-centrifuged Golgi bodies, etc., of Sporozoa, 

 see Miss M. Daniels. Qua)t. Jour. Micr. Set., 1937. 



684. Methods for Cytoplasmic Inclusions (General). The mito- 

 chondria and Golgi apparatus never clearly appear in stained 

 sections prepared by such methods as fixation in corrosive acetic, 

 Gilson, Bouin, Carnoy or Flemming-with-acetic acid, and staining 

 in Ehrlich's ha?matoxylin and eosin, toluidin-blue and eosin, 

 paracarmine and borax carmine. Though the mitochondria 

 and Golgi apparatus are properly fixed by formalin, Miiller, 

 Flemming-without-acetic acid, Champy, Altmann, etc., they 

 will rarely appear visible in stained sections which have been 



