388 RESEARCH IN PROTOZOOLOGY 



after the crisis of an acute infection). It will usually take place 

 within fifteen minutes after the blood is drawn. 



15. Staining. If a permanent preparation is to be made either 

 Wright's stain or Giemsa's spirochete stain may be used. The 

 former is the quicker, but in the writer's experience at least, the 

 latter is more consistently satisfactory, and gives somewhat sharper 

 stains. Such stains as hemotoxylin will not give satisfactory re- 

 sults with malarial parasites. Thick smears are not practicable both 

 because of the excessive quantity of blood required, and because 

 the nuclei of the red cells obscure any parasites which may be 

 present. 



The technique for making these stains follows : 



a. Wright's stain 



For Wright's stain the smear should be flooded for two min- 

 utes with the stain, after which an equal amount of distilled water 

 is added and the mixture allowed to remain on the slide for four 

 minutes more. It is then poured off and the preparation washed 

 and allowed to dry. 



h. Giemsa's stain 



If Giemsa's stain is used the smear must first be fixed in 

 methyl alcohol (absolute) for one or two minutes. It is then rinsed 

 in running water and flooded with the stain, which is to be made 

 up fresh each time it is used by taking one and one-half drops 

 of the prepared stain and mixing it with one cubic centimeter of 

 distilled water, up to whatever quantity may be required (from 

 one to two cubic centimeters are required per slide). Twenty or 

 thirty minutes are usually required to secure a good stain. 



16. Experimental work with drugs. If experimental work de- 

 signed to test the effects of various drugs upon the infection is to 

 be done it is usually best to administer the drugs orally. This can 

 be most easily done with a small Luer syringe of one cubic cen- 

 timeter capacity or less, using a large size Luer needle from which 

 the point has been cut for the purpose. The needle is then bent in 

 such a way that the end can be conveniently thrust a little way 

 down the throat of the bird, and it will be found that measured 

 amounts of the solution can be given with very little regurgitation. 

 It is of course important to see to it that no sharp edges remain 

 on the cut end of the needle, or injury may be done to the bird's 



