PROTOZOA 587 



1157. Mallory's triple stain is useful for differentiating 

 tissues containing jiarasites. Mallory {Pathol. Techniqne, 1918, 

 p. 112) fixes in Zenker's fluid before using this stain, but Caklkton 

 (op. cit., 1926, p. 132) obtains excellent results after his sublimate- 

 formol, and says that material fixed in Bouin can be improved by 

 placing the sections for about a minute in a saturated aqueous 

 solution of sublimate and then washing it out well before proceed- 

 ing with the stain. He differentiates the mixture as well as the 

 fuehsin in tap-water, since all these stains can be washed out in 

 dilute alkalies. Mallory (1918, p. 112) stains sections in 0-5 per 

 cent, aqueous solution of acid fuehsin for a few minutes (two to 

 four), then transfers to the following solution for ten to twenty 

 minutes or longer : 



Anilin blue soluble in water ((iriibler) . 0-5 grm. 

 Orange G (Griibler) . . . . 2-0 ,, 



1 per cent, aqueous solution of phospho- 



molybdic acid . . . .100 c.c. 



The sections are then washed and differentiated in tap-water, 

 dehydrated rapidly and mounted. 



Collagen fibrils, reticulum of connective tissue, mucus, chitin, 

 etc., stain blue ; nuclei, cytoplasm, shades of red ; hsematids, 

 yellow^ to orange. Sharp {Univ. Calif. Pub. ZooL, xiii, 1914, 

 p. 58) with a slightly modified method for ciliates obtains the 

 ectoplasm mauve, endoplasm pink, macronucleus orange-brown, 

 micronuclcus and neuromotor fibres bright red. 



1158. Modification of Claudius' method {Annal. Inst. Past., xi, 

 1897, p. 332) of carrying out Gram's stain (§ 373). Although 

 this is not strictly speaking a stain for protozoa, it is often most 

 useful for staining Gram positive organisms such as yeasts, e.g. 

 Histoplasma, Cryptococcus, etc.. in tissues, and preventing them 

 from being mistaken for protozoa. The following is satisfactory 

 for films or sections after good fixation : 



Stain in paracarmine or borax carmine, see §§ 271, 273. 



(There is no advantage in using Ortii's alcoholic carmine as 

 reconnnended by Claudius — ^it tends to macerate and staining 

 is no better than with the usual carmine mixtures.) 



After washing the preparations, transfer them from distilled 

 water to 1 per cent, aqueous solution of methyl violet (or carbol 

 gentian violet) for one to two minutes. 



Rinse in water and treat for one to two minutes with half- 

 saturated aqueous solution of picric acid. 



Remove as much of this solution as possible by blotting round 

 the sections with filter paper. Do not let the preparations dry, 

 however, and decolourise by pouring on a few drops of chloroform 

 and then covering them with clove oil until no more blue colour 

 comes away. They will then appear pinkish and may be washed 

 in xylol and mounted in balsam. 



