15 



that of perfectly uniform disks, this portion of the 

 film should be passed over. If the whole of the 

 film is of this character, it should be discarded. 



2. It is well to have had the parasite 

 demonstrated to one both fresh and stained. After 

 this, little or no difficulty will be experienced in 

 recognizing the parasite when it is really present. 

 Should there be any doubt, the object seen is 

 probably not a parasite. A parasite stained pro- 

 perly by the Romanowsky stain has always a blue 

 body with a bright red dot or dots, and a more or 

 less clear, unstained, whitish (vac-uolic) area. Its 

 definite outline, whether circular or elongated, 

 should be quite clearly made out — then no pos- 

 sibility of mistake should arise. 



3. Artificial bodies in the red cells are gener- 

 ally to be detected by their occurrence in nearly 

 every corpuscle in one portion of the field, and 

 not in another. When a really well-spread portion 

 of the film is reached, they are no longer seen. A 

 common artifect of this nature is a small granular 

 mass stained reddish, apparently in the red cell. 

 It is caused by the staining of vacuoles in the cell. 

 The body has a granular appearance, but the blue 

 body, red spot, xnistained area, and clear-cut out- 

 line of the parasite are quite wanting. 



4. In fresh specimens, crenations or vacuoles 

 may simulate young ring parasites. It is, how- 

 ever, impossible to get a clearly defined edge to 

 these by focussing. Crenations appear as black 

 dots in one focus, and as bright dots in another. 

 Vacuoles have not the peculiar solid look of young 

 parasites, and cannot be clearly focussed. 



5. Masses of bright yellowish-brown pigment 

 derived from the skin are common in films made 



