tissue. Weigert uses a chrom combination for staining nervous 

 tissue. 



Benda uses haematoxylin following treatment with a copper salt 

 for studying spermatogenesis; and Bensley a similar technic for 

 chromosomes and mitochondria. 



Mallory has proposed a formula for haematoxylin containing 

 phosphomolybdic acid and also one containing phosphotungstic 

 acid. The latter method is especially valuable for staining cells in 

 the process of mitosis, and for distinguishing fibroglia, myoglia and 

 neuroglia fibrils from collagen and elastin fibrils, especially in 

 tumors, but also in normal tissues. It brings out sharply the 

 striations in skeletal and cardiac muscle fibers. Haematoxylin is 

 used in combination with other stains, especially eosin, but not so 

 frequently as in the case of the common anilin dyes. The Van 

 Gieson technic calls for haematoxylin followed by picric acid and 

 acid fuchsin. A few other methods call for picric acid or ammonium 

 picrate after haematoxylin; and it is sometimes used with eosin or 

 after orange G or acid fuchsin. Most of these combinations, how- 

 ever, are called for only in the case of special procedures. 



At present it is possible to obtain very satisfactory haematoxy- 

 lin manufactured in America. A very good statement of the situa- 

 tion is given by McClung (1923) . The first American haematoxylin 

 put on the market, altho pronounced very good by many of those 

 using it, still proved to be lacking in some of the qualities which the 

 best haematoxylin ought to possess. Thru the cooperation of the 

 manufacturers, the trouble was located. In order to obtain a pure 

 product, SO2 had been used in the manifacture for bleaching pur- 

 poses; but this treatment was found to be harmful to the haema- 

 toxylin. The product now on the market is not so treated, how- 

 ever, but an extra recrystalization is introduced in the place of the 

 bleaching process; and the resulting product meets all the tests to 

 which it is submitted. 



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