and Laboratory Methods. 2381 



100 c.c. of the alkaline methylen blue solution.) This precipitate is collected on a 

 filter and without washing is allowed to dry. When thoroughly dry a satu- 

 rated solution is made in pure methylic alcohol. (Three-fourths of a grain of 

 the dry percipitate will thoroughly saturate 100 c. c. of the methylic alcohol in a 

 few minutes.) This saturated alcoholic solution of the percipitate is next filtered 

 and 25 per cent, of methylic alcohol added to the filtrate. This somewhat dilute 

 alcoholic solution of the percipitate is the staining fluid. It is permanent and 

 may be kept on hand ready for use, but care should be taken to prevent evapo- 

 ration of the alcohol, thus making the solution too concentrated. 

 Wright's staining technique is as follows : 



1. Make films of the blood, spread thinly and allow them to dry in the air. 



2. Cover the preparations with the alcoholic solution of the dye for one 

 minute. 



3. Add to the alcoholic solution of the dye on the preparation sufficient 

 water, drop by drop, until the mixture becomes semi-translucent, and a yellowish 

 metallic scum forms on the surface. Allow this mixture to remain on the prep- 

 aration for two or three minutes. 



4. Wash in water, preferably in distilled water, until the film has a yellowish 

 or pinkish tint in its thinner or better spread portions. 



5. Dry between filter paper and mount in balsam. 



The blood film is fixed upon the cover-glass by the action of the concentrated 

 alcoholic solution for 1 minute before the dilution. The real staining takes place 

 after the dilution with water. 



The red corpuscles are stained orange or pink, nuclei some shade of blue, 

 acidophile granules eosin color, neutrophile granules reddish lilac, basophile 

 granules of the mast cells dark blue or dark purple, blood plates blue or purplish. 

 The bodies of malarial parasites stain blue, while the color of the chromatin varies 

 from a lilac through varying shades of red to almost black. 

 Massachusetts State Board of Health. Ernest L. WalKER. 



The Museum. 

 VII. 



THE HALL.— Continued. 



The floors of halls, as previously mentioned, should be of hard, easily washed 

 substances. Tiling meets these requirements. Tiling is expensive, and it may 

 be necessary in some cases to resort to a substitute. Wood wears away too 

 easily, but protection to it can be secured by staining and rubbing its surface with 

 a dressing of linseed oil and turpentine, with some admixture of crude oil. 



In this connection it seems altogether feasible to use an asphalt or concrete 

 floor, colored with red or yellow ochre. This can be made durable and hard, is 

 much cheaper than tiling, and admits freely of washing, and, carefully laid down, 

 would probably serve most usefully. 



The height of ceilings in museum halls and the ceilings themselves, their 



