27 
film can be put away and kept indefinitely. If not 
needed the slide is placed on one side with others, 
and eventually cleaned.* 
The Detection of the Malaria Parasite 
We may first note that it is not necessary to 
examine the blood at any particular time, but it is 
very necessary that the patient should net have taken 
quinine previously. Even five grains of quinine may 
so diminish the number of parasites as to make detec¬ 
tion a laborious task, and a negative result under these 
conditions is not conclusive. 
The following forms of parasites may be seen :— 
N.B.—Parasites free in the plasma are practically never seen. 
I. Ring Forms (Fig. 6).—These may be quite 
small, one-sixth of a red cell in diameter, or much 
larger, one-third in diameter. 
Rings are parasites of very distinct outline and 
structure. The part of the parasite that will first be 
noticed in a Romanowsky specimen will be the red 
nucleus, a clearly stained bright red dot (or dots). 
This is generally situated on the margin of the blue 
ring, which is equally distinct in outline, though often 
only a faint blue. The blue ring encloses an un¬ 
stained e vacuolic ’ area. These rings stand out so 
sharply that they appear to project from the corpuscles. 
The red dot generally forms the signet of the ring 
(signet forms), but also may occur in the centre of 
the vacuole. The red nucleus or dot is often also 
* To Clean Dirty Slides 
i. Rub with turpentine (benzine or xylol) to remove any adherent oil. 
2. Wash with soap and water. 3. Rinse in water. 4. Dry and rub well with a 
clean cloth. 
