38 PROTOZOAN PARASITISM 



conditions as above may reasonably exclude pro- 

 tozoal infection. 



The finding of an active amoeba by such examina- 

 tion is merely the first step. It must be now identi- 

 fied. If the case is one of clinical active intestinal 

 amoebiasis, especially with blood stained mucous 

 stool, and an amoeba is found, of active progressive 

 motility, without bacteria and other solid bodies, 

 such as yeasts or crystals, but perhaps containing 

 red blood corpuscles, the presumption is that it is 

 Endarnoeha histolytica. This is allowable because 

 it is advisable to get the individual on proper treat- 

 ment and the diarrhoea may prevent the appearance 

 of cysts for an indefinite period. In such a case 

 the cysts may be hunted when the stool begins to 

 form. 



In other cases search must now be instituted for 

 the cyst, which may or may not be found in a 

 purged stool. If it is not, a formed stool must be 

 obtained. 



Study of amoebic cysts for diagnostic purposes in 

 medical practice amounts to looking for that of End- 

 amoeha histolytica to the exclusion of all others. 

 Amoeba cysts in the stool are rounded, glassy or 

 hyaline bodies, easily overlooked, sometimes very 

 numerous, sometimes not. 



Search for them is facilitated by mixing the particle 

 of stool on a slide with an iodine solution, such as 

 Gram's iodine (iodine 1 part, KI 2 parts, water 100 

 parts). This stains them various shades of brown 



