COCCIDIOSIS IN BIRDS AND MAMiMALS 289 



tion with centrifugation. The various steps in his technique as 

 summarized in his paper are as follows : 



"i. Emulsify the feces in water until their mobility approaches 

 that of water. 



"2. Strain through wire gauze having thirty meshes to the linear 

 inch. 



"3. Mix the filtrate with an equal volume of a solution of sugar 

 in water prepared by dissolving one pound in three-quarters of 

 a pint (sp. gr. 1200). 



"4. Centrifuge for two minutes at 2000 to 2500 revolutions per 

 minute. 



"5. Lift the eggs from the surface of the liquid by lowering 

 a cover-glass into contact with it, which is simply achieved by at- 

 taching the cover-glass to a handle by means of a small 'beak' of 

 plasticine, and on withdrawal detaching this on the surface of 

 a slide." 



The direct centrifugal flotation method used by Lane (1922) 

 for the mass diagnosis of hookworm infestation has been modi- 

 fied (Andrews, 1926) for use in the diagnosis of coccidiosis. 



"Strong Erlenmeyer flasks of sixty-five or seventy cubic cen- 

 timeters' capacity are calibrated and etched to indicate volumes of 

 fifty-six and fifty-eight cubic centimeters. The flask is filled with 

 water up to the level of the fifty-six cubic centimeter mark, and 

 then a sufficient amount of the specimen stool collected at random 

 from various parts of the feces is added to bring the fluid level 

 up to the fifty-eight cubic centimeter mark. Thus two cubic cen- 

 timeters of stool have been added. Four or five cubic centimeters 

 of lead shot (medium size and small, mixed) are poured into 

 the mixture. The flask is closed with a rubber stopper and is 

 shaken until the contents are uniformly mixed. If the stool is 

 hard, it is futile to try to comminute it by shaking with shot unless 

 it has stood in water for several hours. The most convenient 

 routine is to let the stoppered flasks stand with their contents 

 overnight and to shake them the following morning. The thor- 

 oughly emulsified specimen is then poured into a round-bottomed 

 fifty cubic centimeter centrifuge tube which has been calibrated 

 and etched to indicate a volume of forty-five cubic centimeters. The 

 centrifuge tubes are balanced in their cups by the addition of 

 water and are whirled at the lowest speed of the centrifuge (Inter- 

 national Electric Centrifuge, Size i) for two or three minutes. 



