66 Phylum Protozoa 



calcium chloride 0.024 gm., potassium chloride 0.042 gm., sodium bi- 

 carbonate 0.02 gm., dextrose 0.25 gm.). Heat over a hot water bath for 

 15 minutes keeping the medium in - constant motion by revolving the 

 flask. Filter through cotton with a suction pump. Put about 6 cc. of 

 the filtrate into each test tube. Autoclave the tubes for 20 minutes under 

 15 pounds' pressure (Hogue, 1921a). 



Ovomucoid medium. The white of one hen's egg is thoroughly shaken 

 with glass beads in a glass flask. Add 100 cc. of 0.7% sodium chloride 

 solution. Cook this for half an hour over a hot water bath, keeping the 

 contents of the flask in constant motion by revolving the flask. Filter 

 through cotton, using a suction pump. Put about 6 cc. of the filtrate in 

 each test tube. Sometimes one loopful of the egg yolk is added to each 

 test tube. Autoclave the tubes for 20 minutes under 15 pounds' pressure 

 (Hogue, 1921a). 



Sodium chloride sheep serum water. To a flask containing 100 cc. 

 of 0.85% sodium chloride solution which has been sterilized in the auto- 

 clave for 15 minutes at 15 pounds' pressure add 10-15 cc. of sterile sheep 

 serum water. This is prepared by diluting one part of sheep serum with 

 three parts of distilled water and sterilizing in an Arnold steam sterilizer 

 for one hour at ioo° C. for three successive days. Pour the sterile sodium 

 chloride sheep serum water into sterile test tubes. It will have a pH 

 of 7-7.4 (Hogue, 1922a). 



Sodium chloride pig serum water. This is made in the same way as 

 sheep serum water except that one part of pig serum is diluted with four 

 parts of distilled water. It will have a pH of from 6.8-7.4 (Hogue, 

 1922a). 



Sodium chloride sheep serum water modified. This modification is 

 used for Trichomonas buccalis. Take equal amounts of 0.85% sterile 

 sodium chloride solution and sterile sheep serum water. Put 5 cc. in a 

 test tube. This has a pH of 7.7. Just before using, add a small amount 

 of saliva taken from a person who is not infected with T. buccalis (Hogue, 

 1926). 



Deep cultures. "Deep cultures" are used in order to keep organisms 

 for a long time without transferring them (Hogue, 1922a, 1922b, 1926, 

 1933). These are made by putting 15 cc. of the culture to be used into 

 150 mm. test tubes, inoculating them at the bottom of the tube with a 

 long pipette and then covering the medium with a layer of sterile paraffin 

 oil. This prevents evaporation but does not make the cultures anaerobic. 

 Under these conditions the animals do not divide so rapidly and do not 

 form such large quantities of waste products. In these "deep cultures" 

 they live for weeks or months, depending on the species. 



