2. =Trichomonas vaginalis and intestinalis=; =Cercomonas coli=; =Megastoma entericum=; =Balantidium coli=; =Pyrosoma bigeminum=; =Trypanosoma=; =Leishman-Donovan bodies=, and allied forms are best stained with the modifications of Romanowsky’s stain; the chromatin is red-violet (macro-nucleus red, micro-nucleus black, flagellum red, protoplasm blue, basophilic granules black). For staining in sections mercuric chloride or Zenker’s fixation followed by staining with polychrome methylene-blue, Giemsa’s or the modifications of the Romanowsky method may be employed. 3. =Plasmodium Malariae.= For films make medium smears (not too thin); fix with equal parts of absolute alcohol and ether for ½-1 hour; or fix and stain in the same solution (Leishman-Romanowsky, Wright’s stain, etc.). For single staining methylene-blue, carbol-thionin, etc., may be employed; for double staining eosin and methylene-blue. Ehrlich’s tri-acid, or any of the eosin-methylene-blue combinations may be used (particularly the Leishman-Romanowsky or Wright’s). With the Romanowsky methods the body of malarial organism is stained blue, the chromatin varying shades of lilac, red, purplish-red or almost black. When the blood contains but few parasites 1 cc. may be drawn, mixed with 20 cc. of distilled water and centrifugated. Smears are then made of the sediment. For the staining of the plasmodium in imbedded tissues the following method is recommended by _Bignami_. The tissue should be fixed in formol or mercuric chloride, preferably a mixture of mercuric chloride 1 grm., sodium chloride 0.75 grm., acetic acid 0.75 grm., water 200 cc. Fix for 2 hours; after-harden in alcohol and iodine-alcohol, changing the alcohol each day for seven days. Dehydrate in absolute alcohol, and imbed in celloidin or paraffin. Stain in a saturated watery solution of magenta or in a mixture of equal parts of saturated alcoholic mixtures of magenta and orange G. Good results may, however, be obtained with Löffler’s methylene-blue. Clear in xylol; mount in balsam. 4. =Coccidia and Sarcosporidia.= The ordinary fixations give good results. Imbed in paraffin or celloidin. Weigert’s iron-hæmatoxylin and Van Gieson’s give as good pictures as any of the special methods advised.