426 SUMMARY OF CaRllENT RESEARCHES RELATING TO 



1,800'revolutions per minute. Throw away the supernatant liquid, leav- 

 ing the residue as before. This residue is now free from fat, blood 

 corpuscles, and a great part of the bacteria, and contains only protozoal 

 cysts, oocysts, helminth eggs, and food debris of high density. The 

 residue may be taken up with the capillary pipette, mixed with double 

 strength lugol solution and examined under the Microscope. 



Two Rapid Methods for Searching for Malarial Crescents.''— 

 L. Tribondeau and J. Dubreuil describe the two following methods for 

 the rapid identification of malaiial crescents in blood films : — 1. Puncture 

 the lobe of the patient's ear and take up several drops of blood with a 

 capillary pipette: transfer directly into a mixture of absolute alcohol 

 10 parts and distilled water 2«» parts. Mix well by shaking. When the 

 blood is ha^molyzed, centrifuge. Decant and reject the supernatant 

 fluid. Centrifuge again and emulsify the residuum in a little of the Hquid 

 that collects at the bottom. Spread the emulsion on slides and allow to 

 dry. Fix with alcohol and stain for about ten seconds with ammoniacal 

 polychrome-blue (Tribondeau and Dubreuil). 2. Place a large drop 

 of blood upon a slide at one extremity. Incline the slide and draw 

 the blood along the slide, by means of a rod, to the other extremity. 

 Place fiat, in order to obtain an even layer of blood, and dry in the 

 air without warming. Dehaimaglobinize and sprinkle with 1 in 8 

 alcohol, renewed several times. Fix with alcohol and stain as above. 

 Examine the preparations with the oil-immersion lens. The leucocytes, 

 with their blue nuclei, can be clearly seen, standing out against a back- 

 ground of lysed-red cells. The crescents are easily recognized by their 

 masses of brownish-black pigment and by their characteristic shape. 



Nematode Technique.!— T. B. Magath, in No. 77 of the " Contri- 

 butions from the Zoological Laboratory of the University of Illinois," 

 gives an excellent account of his own experiences and the results of other 

 workei's in obtaining success by means of careful techni<pie. The paper 

 is illustrated by six diagrams of various apparatus which the author has 

 found useful. 



(4) staining- and Injecting-. 



Distilled Water for Microscopical Stains.^— L. Tribondeau points 

 out that absolutely pure and neutral distilled water should only be used 

 in staining by Leishman, Gierasa, etc. In testing the reaction of water 

 for such purpose, one drop of an aqueous (1/100) solution of helianthin 

 should be employed. If the colour obtained is orange or rose, the water 

 is acid ; if the tint is yellow, the water is neutral or alkaline. In order 

 to recognize alkalinity one adds, little by little, to a vessel containing 

 water tinted yellow with a drop of helianthin, sufficient sulphuric acid 

 solution (I grm, to the litre) to produce a pale orange coloration. Add 



* C.R. Soc. Biol. Paris, Ixxx. (1917) pp. 494-5. 



t Trans. Amer. Micr. Soc, xxxv. (1916) pp. 245-56 (6 figs.). 



X C.R. Soc. Biol. Paris. Ixxx. (1917) pp. 388-9. 



