8 



Tee Naturalist. 



Kleinenberg's original prescription is as follows : — 



Sol. 1.— Add alum to saturation to a concentrated solution of 



chloride of calcium in 70 % alcohol. 

 Sol. 2. — Make a saturated solution of alum in 70 % alcohol. 

 Mix solutions 1 and 2 in the proportions of 1 to 8, and add the 

 Hoematoxyliii previously dissolved in alcohol. 



More recently Kleinenberg has simplified his method by taking 

 only the first-named solution and diluting it with six to eight times its 

 bulk of 70 ~z alcohol, and when wanted for use adds the requisite number 

 of drops of Hoematoxi/lm dissolved in absolute alcohol. After staining. 

 Kleinenberg allows his objects to remain in 90 % alcohol. By the 

 bringing together of chloride of calcium and alum, a precipitate of 

 gypsum is formed ; so that probably it would be better to use 

 chloride of aluminium in the first instance. 



The staining is best done, so far as small objects are concerned, in 

 a very weak solution of HcBmatoxylin. A longer time is of course 

 required for the process, but the objects come out sharper and brighter 

 than they otherwise would. If it is required to dilute a strong 

 solution of HcBmatoxylin, this must be done by means of solution 

 No. 1. Alcohol would cause a slight precipitate, which would 

 interfere with the transparency of the objects when stained. The 

 chloride of calcium is, according to Kleinenberg, only necessary to 

 set up a circulation between the alcohol contained in the tissues and 

 that outside. If one works with a strong solution, a little over- 

 staining is apt to result, and this should be removed by.steeping in 

 acid alcohol. For this purpose Kleinenberg recommends oxalic acid 

 or hydrochloric acid (i %), and the objects must be allowed to remain 

 in the liquid until a slight red tinge makes its appearance. On again 

 placing the object in pure alcohol, it will assume its proper blue 

 violet colour. 



Cochineal. — This medium is very similar in most respects to 

 BcEmaioxylhi. It supplies a dye similar to carmine, which may be 

 used with advantage where the thickness of the walls, or other peculi- 

 arity of the object forbids the use of an aqueous solution of carmine. 

 It is particularly suited for the ArtJiropoda, whose chitine it is well 

 known, only allows the dye to penetrate with difficulty, but it is also 

 suitable for all objects desired to be stained in an alcoholic solution^ 

 Its preparation as well as its use is most simple— ordinary com- 

 mercial powdered cochineal is left to steep in 70 % alcohol for several 

 V-- For a gramme of cochineal take 8-10 cubic centimetres of 



