234 PROTOZOAN PARASITISM 



acteristic structure, once recognized, makes it easily 

 differentiated and identified. 



In thin smear preparations it is well stained by 

 ordinary blood film methods, the peripheral zone, 

 nuclei, and central body being differentiated. In 

 iron-haematoxylon preparations the central body is 

 dark, the peripheral zone lighter and the nuclei 

 deeply stained. 



In various of the mediums used for culture of in- 

 testinal protozoa it often grows when it has not been 

 seen in the feces. 



Although Blastonjstis is an intestinal inhabitant 

 of most or all people and has been seen very com- 

 monly in stool examination and culture we really 

 know very little about its life. Its main importance 

 at the present time lies in the need for its recognition 

 by medical and other laboratorians. 



