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Malignant Tertian. —I. The rings of this species 
are the smallest, one-sixth to one-seventh the diameter 
of a red cell. Instead of being ring-like they may 
stretch across the cell (bacilliform), or be applied to 
the margin of the cell (Plate I). Pigment is generally 
absent, at least in the tropics. It must, however, be 
admitted that it is difficult to be certain of the species 
of a single isolated ring. 2. The largest stage in the 
blood is characteristically egg-shaped, one-third to 
one-fourth the red cell. These forms occur (in 
regular charts) when the temperature is low. If, on 
the contrary, the temperature is still high, and large 
forms are found, they are probably simple tertian or 
quartan. 3. The infected red cell shews occasionally 
