232 THE AMERICAN MONTHLY [Aug. 



The Use of Ruthenium Red in Plant Histology. 



Translated and Condensed, 

 By A. B. AUBERT, 



ORONO, ME. 



At the meeting of December 26th, 1892, of the French Acad- 

 emy of Sciences, Mr. A. Joly presented a paper upon the am- 

 moniacal compounds ofthesesquichloride of rutlienium. Among 

 these compounds is: Ru2 (O H)2 CU (N H3 )7 3 H2 which 

 is formed by adding very finely divided anhydrous sesquichlo- 

 ride of ruthenium to a cold solution of ammonia. If this be 

 kept at a temperature of 40° for some time the liquid becomes 

 deep red and when sufficiently concentrated small brown crys- 

 tals of the above formula separate out. The solution of this 

 compound is red, seen by transparence, but of a violet hue when 

 viewed by reflection. It has such strong tinctorial powers that 

 it may fitly be compared with the organic dyes. 



At the meeting of March 20th, 1893, Mr. L.Mangin, presented 

 a paper upon the application of this ruthenium red or oxychlo- 

 ride of ruthenium to vegetable histology. 



He says that from its chemical composition and behavior with 

 acids and alkalies it must be looked upon as a basic stain char- 

 acterized by its inertness as regards cellulosic compounds and 

 its power of staining pectic compounds with varying degrees of 

 intensity. 



The stain is not decolorized by alcohol or glycerine and sec- 

 tions stained with it may be dehydrated and mounted in Canada 

 Balsam. It fixes itself energetically upon mucilage derived 

 from pectic compounds, but does not stain that derived from cel- 

 lulose. 



The introgenous compounds in plants are unequall}^ stained 

 and always with less energy thanp)ectic derivatives ; thenucleus 

 and granular protoplasm stain with varying intensity, the proto- 

 plasm staining but slightly. The above results refer more par- 

 ticularly to fresh tissue preserved in alcohol. By treating the 

 sections with alum or neutral acetate of lead the affinity of the 

 nucleus and protoplasm for the stain become more energetic. 



To take aniline stain out of cloth.— Dissolve one part of 

 Sodium Nitrate in two parts of dilute sulphuric acid and 75 

 parts of distilled water. Let it stand over night. Apply gently 

 and rinse carefully. 



