and Laboratory Methods. 2317 



allowed to mix with the alcoholic solution of the dye. The film is then allowed 

 to stain for 5 minutes, then gently washed off with distilled water, and a few 

 drops of the water allowed to rest on the film for 1 minute, when the prepara- 

 tion is ready for examination, either directly in water or after drying and mount- 

 ing in balsam. "The part of the procedure in which the stained film is allowed 

 to soak in distilled water for a minute after staining and washing has a triple 

 importance. It intensifies the Romanowsky staining, it removes the remains of 

 the deposit, and it alters the tint of the red blood corpuscles from a greenish blue 

 to a transparent pink." 



Red blood corpuscles are stained pale pink or greenish, semi-transparent. 

 The polymorphonuclear leucocytes (neutrophiles ?) have a nuclear network stained 

 a deep ruby red color with sharply defined margins, extra-nuclear protoplasm 

 colorless, granules red. The eosinophil leucocytes show a ruby-red nucleus 

 and pale pink granules. Mononuclear leucocytes have the nucleus ruby-red 

 with extremely sharp, clear outlines ; extra-nuclear protoplasm eau-de Nil or 

 blue, occasionally showing a few red granules. Lymphocytes the same as the 

 mononuclears, except that the nuclei are, as a rule, more deeply stained. Baso- 

 phile leucocytes have the nucleus red, but usually more or less marked by gran- 

 ules overlying it ; granules very deeply stained a deep purplish black. Nucle- 

 ated red corpuscles have the nucleus stained almost black, with a sharp outline ; 

 extra-nuclear portion gray. Blood plates are deep ruby-red color with spiky 

 margins, frequently showing a pale blue peripheral zone surrounding the red 

 center. Malarial parasites stain blue and their chromatin ruby-red ; in case of 

 the tertian parasite Schiiffuer's dots are well marked in the containing red cor- 

 puscle. Bacilli are stained. 



Renter (1901) worked on a similar line as Leishman and also succeeded in 

 isolating the active staining ingredient of the eosin-methylen blue compound and 

 applying it as a single stain. He also used absolute alcohol as a solvent of the 

 neutral dye, a separate process of film fixation occupying at least an hour, and 

 his staining process in itself occupies 2 or 3 hours. 

 Massachusetts State Board of Health. ErneST L. WalKER. 



Methods in Plant Physiology. 

 XI. 



XI. GEOTROPISM.— Continued. 



9. Effect of Different Media upon Geotropic Curves. As has been shown by 

 Nemec^ the shape of the curve of an inverted root depends to a large extent 

 upon the nature of the medium in which it is grown. Figure 14 shows some of 

 the curves which may be produced by different media. 



Raise seedlings of Lupinus albus or of Vicia Faha in wide crocks of moist 

 sand or sawdust ; when they have attained a length of 3 to 5 cm. invert the 

 crocks and allow the seedlings to grow for two days in that position. Employ 

 seedlings of the same kind for experiments with gelatine, moist air, and water. 



1 Nemec, B. Jahrb. f. wiss. Bot. Bd. 36, p. 80. 



