Animal Parasites 389 



Diamond (1943) added 1 drop of Tergilol #7 (Carbide and Carbon 

 Chemical Corporation) to the diluted hematoxylin solution just be- 

 fore use (1 drop per 30-40 ml. solution). This he substituted for heat; 

 it reduces surface tension and increases cell penetration. Reduced 

 staining time to 5 minutes. 



This method may be used for amoebae in tissue as well as in 

 smears. 



Lawless' Rapid Method (1953) 



The staining method may be used for either Schaudinn's or Schau- 

 dinn-PVA fixed material. 



solutions: 



Schaudinn's fixing fluid, see page 21. 

 Schaudinn-PVA fixative: 



With stirrer going at high speed, sift 25 gm. PVA powder (Elvanol, 

 grade 71-24*5) into the vortex of a cool (20°C) solution of 312 ml. 

 saturated aqueous mercuric chloride, 7.5 ml. glycerine, 25 ml. glacial 

 acetic acid and 156 ml. 95% ethyl alcohol. After 10 minutes and 

 while still stirring, heat in water bath to 75-85°C: 5-8 minutes, or 

 until solution is complete. If solution gels during storage, warm in 

 56 °C water bath. Some protozoa fix better in warm PVA fixative. 



Stain: 



chromotrope 2R, C.I. 16570 0.6 gm. 



light gi-een SF, yellowish, C.I. 42095 0.15 gm. 



fast green FCF, C.I. 42053 0.15 gm. 



phosphotungstic acid 0.7 gm. 



glacial acetic acid I.O ml. 



distilled water 100.0 ml. 



Add acetic acid to dyes and phosphotungstic acid, let stand 15-30 

 minutes. Add water. 



procedure: 



A small portion of stool is fixed in PVA fixative (1 part stool to 3 

 parts fixative): 15 minutes to 1 hour or more. In this form it can be 

 shipped in a vial. When ready to make slides, decant off excess PVA 

 solution. Replace cap of vial and shake the emulsion. Remove cap 

 and cover vial opening with gauze. Place 3 or 4 drops of strained ma- 

 terial on cleansing tissue or blotter. Allow absorption of PVA for 

 about 5 minutes. Scrape up moist residue and smear on slide or cover 



•DuPont de Nemours and Co. 



