and Laboratory Methods. -315 



Demonstration of Fibro-Vascular Bundles. 



Partly dead leaves of the Agave have been found especially good for this 

 demonstration. Petioles of plantain, Calladium, or celery, or dried corn stalks 

 are very commonly used for this purpose, but when these are not available, the 

 partly dried leaves of small Agaves may be used to advantage. Fresh leaves 

 will answer still better. After the epidermis of the leaves has been cut around, 

 the leaf may be pulled apart. The fibro-vascular bundles will then appear as 

 fine silken fibres, resembling threads of cobweb, much as is seen in Calladium 

 petioles, only more numerous. By placing a length of the leaf in a solution of 

 eosin or red ink the usual demonstration of these bundles as the path of the 

 water current may be made. C. Stuart Gacer. 



N. Y. State Normal College. 



A Review of the Methods of Staining Blood. 



VIII. 



D. Neutral Stains. — Continued. 



Argiitinsky (1901) recommends the following modification of the Romanow- 

 sky-Nocht stain for staining malarial blood : Two stock solutions are made 

 up,— 



a. Jy^ per cent, eosin. 



b. Soda-methylen blue, prepared by heating 48 hours in a warm oven (55°- 

 60°C.) 100 c. c. of 1 per cent, methylen blue with 6 c. c. of 5 per cent, solution 

 of soda. 



Three cubic centimeters of the soda-methylen blue solution are mixed with 

 42 c. c. of distilled water. In another dish 5 c. c. of the yL per cent, solution 

 of eosin are mixed with 25 c. c. of distilled water. The two diluted solutions 

 are then slowly stirred together. Blood films are placed in this staining solution 

 for 15 to 20 minutes. The metallic film which forms on the surface of the stain 

 is removed with filter paper before the preparations are taken from the staining 

 dish. The preparations are washed 1 to 2 minutes in a series of dishes of dis- 

 tilled water, and after drying between filter paper are mounted in balsam. 



Argutinsky also employs the same stock solutions undiluted with subsequent 

 differentiation. In this case the stock solutions are allowed to ripen at least 5 

 days before use. To 15 c. c. of the 1 per cent, soda-methylen blue solution, 6 

 c. c. of the 1 per cent, eosin solution are added and thoroughly mixed. The 

 metallic film on the stain should be removed with filter paper before the prepar- 

 ation is removed from the stain. It is then rinsed in water and placed in the 

 dififerentiating fluid (120 c. c. of 95 per cent, alcohol, to which 4 or 5 drops of 

 glacial acetic acid and 2 c. c. of 1 per cent, aqueous solution of eosin have been 

 added). The preparation is moved to and fro in this solution, the superfluous 



