186 CHAPTER XIII. 



and precipitates. To avoid this the mixture should be made 

 up in two separate bottles, each containing half of the alcohol 

 and of the acid, and one containing besides all the calcium 

 chloride, the other all the haematein and all the aluminium 

 chloride, equal quantities being taken from each when re- 

 quired for staining. 



With certain objects this solution does not penetrate well, 

 the stain being confined to their superficial parts. This may 

 be remedied by acidifying the solution, or, which is better, 

 by leaving the objects for some time before staining in acid 

 alcohol. Anyway objects ought NOT to have an alkaline re- 

 action. If these precautions be taken, it will not be necessary 

 to use acid for washing out. For some objects also (e. g. 

 Hydroida) the penetrating effect is enhanced by diluting the 

 solution with one third volume of glycerin, or by increasing 

 the proportion of aluminium chloride up to about eight times 

 that of the haematein. 



The solution is not recommended as giving as good results 

 as hasmalum, as a stain it is distinctly inferior ; and Mayer 

 is of opinion that no alcoholic haematein solution can be made 

 to give as precise a stain as the aqueous solutions. He 

 recommends it merely as a substitute for Kleinenberg's (in 

 cases in which an alcoholic haematein stain seems indicated), 

 as being convenient, easy to prepare, and constant in its 

 effects, none of which qualities belong to Klemenberg's 

 formula. 



247. APATHY'S Haematein Mixture I A (Mitth. Zool. Stat. 

 Neapelj xii, 1897, p. 712). Make (A) a solution of 9 per 

 cent, alum, 3 per cent, glacial acetic acid, and 0*1 per cent, 

 salicylic acid in water, and (B) a 1 per cent, solution of 

 haematoxylin in 70 per cent, alcohol, preserved for six to 

 eight weeks in a bottle not quite full. Mix one part of A 

 with one of B and one of glycerin. The solution will keep 

 for years, and stains either sections or material in bulk. 

 Apathy uses it for staining nerve " primitive-fibrils ;" it is r 

 therefore, not a purely nuclear stain. 



248. KLEINENBERG'S Haematoxylin (Quart. Journ. Micr. Sci., Ixxiv, 

 1879, p. 208). Highly irrational and very inconstant in its composition and 

 its effects; see earlier editions; also the elaborate criticism of MAYER 



