GOLGI BODIES ETC. 309 



35° C. for twenty-four hours ; rinse in aq. dest., not tap-water. 

 Stain twenty-four hours in this sohition : — 1 grm. of pure crystals 

 of haematoxyhn in 10 c.c. of absolute alcohol, added to 10 c.c. 

 of glycerin and 80 c.c. of aq. dest. Differentiate in 5 per cent, 

 iron alum, watching process under microscope. The main point 

 is to avoid washing out the mordant too much when the slides 

 are being transferred from the iron alum to the haematoxyhn. 

 Permanent stain, very good for vertebrate tissues. See also 

 CowDRY, Amer. Journ. Anat., xix, p. 441. We find ordinary iron 

 hsematoxylin is quite good after Regaud fixation. 



700. Kruozynski's* Mitochondrial Method. This simple method has 

 been found useful by Miss J. C. Hill {Arch. f. exper. Zellf., 1936). Fix 

 in Cajal's fluid overnight, or a shorter period for more delicate material. 

 Transfer to 5 per cent, bichromate for three days, wash out under tap, 

 imbed, section in wax and stain in ordinary iron-alum haematoxyhn. 



701. Bensley-Cowdry Acid Fuchsin and Methyl Green Stain 



(CowDRY, Contrih. Carnegie Inst. Wash., viii, 1918). Fix as for 

 Regaud, either by immersion or injection ; formalin should 

 be neutralised in magnesium carbonate, and, if possible, the 

 fixation should be done in an ice-box, but this is not necessary. 

 Pass sections down to aq. dest. tlirough toluol (or xylol), absolute 

 alcohol, etc., thirty seconds in each ; transfer to 1 per cent, 

 potassium permanganate for thirty seconds, but time must be 

 determined experimentally ; then 5 per cent, oxalic acid for 

 thirty seconds. {Note. — The permanganate and oxalic acid 

 may generally be omitted.) Then rinse in several changes of 

 aq. dest. for about one minute (incomplete washing prevents 

 staining in acid fuchsin). Stain in Altmann's fuchsin (§ 694) 

 as follows : dry around sections with duster, add stain, warm 

 over spirit lamp until fumes come off ; cool for six minutes ; 

 wipe around sections with duster, rinse off in aq. dest., so that 

 the only remaining stain is in the sections (or a precipitate 

 forms with the methyl green) ; pipette a little 1 per cent, methyl 

 green over the sections for about five seconds at first, modify 

 time as experimentally found convenient ; drain off excess, 

 plunge into 95 per cent, alcohol for a second or two. Rinse 

 in absolute alcohol, clear in toluol, mount in balsam. Difhculties 

 are that the methyl green may remove the fuchsin (due to 

 incomplete chrome mordanting during fixation), or the fuchsin 

 may have overstained (due to too much mordanting). Some- 

 times, if the methyl green is too weak, it is better to omit the 

 95 per cent, alcohol, dehydrating in absolute. The difficulties 

 of this modification of Altmann's stain are easily overcome ; 

 we have used it for a senior histology class, and with success. 

 Like the Champy-KuU method, this stain is not so permanent as 

 iron hsematoxylin. See also Bensley, Amer. Journ. Anat., xii, 

 p. 308 ; DuESBERG, ibid., xxi, p. 469. 



* Compare Benoit fluid, § 707. 



