14 THE MICROSCOPE. 



whether the individual grains could be well preserved for a long 

 time, for they form an interesting addition to our cabinet. Our 

 method of preserving the starches is as follows: 



It is necessary first to have some aniline blue staining fluid, 

 which we make after the formula given by Beale: 



Soluble aniline blue, y^, grain. 

 Distilled water, i ounce. 

 Alcohol, 25 drops. 



A mixture is made of equal parts of glycerine and water to 

 which is added a very little acetic acid, only two or three drops to 

 the ounce. 



To this mixture of slightly acidulated dilute glycerine is added 

 the aniline blue staining fluid until the whole mixture is of a decided 

 blue color. 



A drop of this mi.\ture is placed on a glass slide and some of 

 the starch to be mounted is dusted over the top. This dusting can 

 be done to the very best advantage by touching the starch with a 

 camel's hair brush and then slightly shaking the brush over the 

 drop of colored glycerine. 



The starch .soon sinks in the mixture and the cover is applied. 

 This method of dusting the starch is much better than stirring it in 

 the mixture with a fine needle which almo.st invariably results in an 

 admixture of air. 



After the cover is apj^lied it is pressed down quite firmly against 

 the slide and all excess of the glycerine carefully removed. The 

 slide is then transferred to the turn-table and a thin layer of dam- 

 mar or baLsam-in-benzole placed around the border of the cover. 

 This soon hardens and in a day or two we can finish with the white 

 zinc or Brunswick black or other cements. 



The effect of thus mounting the grains of .starch is this: the 

 grains themselves have not taken the staining in the least, neither 

 will they ever take it; they retain their natural appearance surround- 

 ed everywhere by the blue glycerine, and the effect is most beautiful. 



Specimens are in our pos.session that were mounted over a year 

 ago in this way and they are as perfect as the day they were pre- 

 pared. — (L. R. -S.) 



