ZOOLOGY AND BOTANY, MICEOSCOPY, ET(;* 239 



alcohol. (3) Stain in anilin bine, using a 1 p.c. solution in 90 p.c. 

 alcohol, diluted with four times its volume of 90 p.c. alcohol. We 

 prefer to make a fresh solution every time we have anything to stain. 

 It is not necessary to measure it. A little of the powder — about half 

 the bulk of a grain of wheat — in ;»0 c.cm. of 90 p.c. alcohol, will give 

 an efficient solution. The time required for successful staining will 

 vary from 3 to 30 minutes. Do not put all the material into the anilin 

 blue at once, but, by trying a few filaments at a time, find out what the 

 probable periods may be. (4) Rinse off the stain in 90 p.c. alcohol, 

 and then treat for a few seconds in acid alcohol (1 very small drop of 

 HCl to 30 c.cm. of 90 p.c. alcohol). The acid alcohol fixes and 

 brightens the anilin blue, but extracts the Magdala red. If the anilin 

 blue or the acid alcohol acts for too short a time the blue will be weak : 

 if they act too long, the red is lost entirely. If the blue overstains too 

 much, wash it out in 95 p.c. alcohol. If the red overstains, wait until 

 the mount is finished, and then reduce the red by exposing the slide to 

 direct sunlight. (5) Absolute alcohol, 5 or 6 seconds. (G) Transfer 

 quicMij to 10 p.c. Venetian turpentine and proceed as in the previous 

 schedule. 



The surprising beauty of successful preparations will compensate 

 for whatever failures may occur. Nuclei and pyrenoids should show a 

 brilliant red, while the chromatophores and cytoplasm should be dark 

 blue. The cell walls should show a faint bluish color. 



Haidanliainh Iron- Alum HsematoxyUn and Eosin. — Follow the 

 schedule for iron-h£ematoxylin until the glycerin has been washed out 

 in 95 p.c. alcohol. Then stain for a minute in a solution of eosin in 

 95 p.c. alcohol. Wash for a minute in 95 p.c. alcohol, then a minute 

 in absolute alcohol, and then transfer to the 10 pc. Venetian turpentine. 

 Other stains may be used. Aqueous stains should be used before 

 starting with the 10 p.c. glycerin. Alcoholic stains should be in strong 

 alcohol — about 90 p.c. — and should be applied just after washing out 

 the glycerin. This method is equally good for filamentous fungi and 

 also for the prothallia of Equisetum and ferns, for delicate liverworts 

 and mosses, and similar objects. 



C6) Miscellaneous. 



Concentration of Malaria Plasmodia.* — C. C. Bass and F. M. 

 Johns have devised a method of concentrating malaria parasites, the 

 fuudamentiil principle involved being that the malaria plasmodium with 

 its host erythrocyte is larger than the non-parasitized blood-cell, and 

 that when centrif uged at the proper speed for a sufficient length of time, 

 the larger cells rise to the top of the cell column, while the smaller cells 

 collect beneath. The leucocytes, being still larger, rise to the surface of 

 the tube. 



Measure 0*2 cm. of citrate-dextrose solution (50 grm. sodium 

 citrate and 50 grm. dextrose in sufficient distilled water to make a 

 volume of 100 c.cm.) into a large tube. Draw 10 c.cm. of blood 



* Amer. Journ. Trop. Diseases and Prevent. Med. iii. (1915) pp. 298-303. 



