The Identification of Intracellular Structures. 109 



Gohji Apparatus. — In the form of a reticulum, of rods often 

 branched, but rarely of granules like mitochondria. When reticular 

 the apparatus is easily distinguished from mitochondria, which in 

 only one clear case are known to form a reticulum (Meves, Apis 

 mellifica, spermatocyte, 9) ; in this case a Golgi apparatus is other- 

 wise present. Golgi elements may break into irregular grains 

 during dictyokinesis (cells of Descemet's membrane of eye, 23), or 

 they may form hollowed grains as in some eggs (Ascidia). If in 

 the lorm of rods, the latter are banana-shaped and curved with 

 tapering ends (Helix, etc.). In most cells, excepting some eggs, the 

 Golgi elements are few in number, much less so than the mito- 

 chondria ; moreover during cell division they generally keep within 

 the zone of the asters, sticking to the fibres of the aster. Mito- 

 chondria may do this, but it is rare. 



MitochondoHa. — These are nearly always either grains which 

 are very numerous, or unbranched rods (chondriokonts). If rod- 

 shaped, the rods are rarely semilunar, and not drawn out at the 

 ends, but are of uniform thickness. Mitochondria are rarely 

 associated with concentrated regions of the cytoplasm (archoplasm), 

 and rarely form a reticulum like the Golgi apparatus. 



Fat and Yolk may exist in the form of more or less numerous 

 spheres, much like mitochondria morphologically, and great care 

 must be taken to avoid confusing them with mitochondria. 



Modus Operandi of the Methods of Kopsch, Kopsch- 

 Altmann, S jovall and. Ca jal, etc. .^ 



I. Kopsch Method. — Fresh tissue, not exceeding 5 mm. in diam., 

 thrown into 6-10 c.cm. of 2 p.c. OSO4 in aq. dist. Left from one 

 to two weeks, in the dark, in airtight vessel. Use glass-covered 

 capsule or bottle. Wash in running water overnight (or a few 

 hours will do), up-grg,ded alcohols, xylol, embed in wax, section 

 3-6 yu., and mount unstained sections in xylol-balsam. Golgi 

 elements, fat, and larger yolk discs black ; mitochondria from 

 yellowish to brown. 



II. Sjovall Method. — Tissue, pieces of which may be faii'ly 

 large, previously fixed (two days) in a suitable formalin strength 

 (5-20 p.c. ?), then washed from one to two hours in running tap- 

 water, transferred to 2 p.c, OSO4 in aq. dist. (see that there is 

 enough according to size of piece treated), and left from two to 

 fourteen days, as for Kopsch. Golgi elements, generally mito- 

 chondria and always fat, and often yolk, black. (Formalin best 

 neutralized with sodium carbonate.) 



III. Kofsch-Altrnann. — Prepare sections by Kopsch, stain as 

 follows in Altmann : — Bring sections to water, stain in acid-fuchsin 

 in aniline water (saturated solution), placing slide on oven or over 

 Bunsen burner till the liquid steams ; leave half to two minutes. 



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