Organic Substances 63 



addition, a number of others, such a fibrin, hyaluronic acid, 

 various undefined glycoproteids of connective tissue, poly- 

 saccharides of bacteria, and fungi,^^ kerasin in Gaucher's dis- 

 ease,^^ lipofuscin,^^ ceroid,^^ and an unidentified substance 

 in the foamy cells of Whipple's disease. ^^ In general, the 

 purple-red shade obtained after periodate oxidation is much 

 more brilliant than that obtained after chromic acid. The 

 permanganate method of Casella^^ is not standardized well 

 enough to be recommended for routine use. 



Some mucoid substances which stain faintly, irregularly, or 

 not at all by the aldehyde techniques are heparin ( mast cell 

 granules; marked species differences), chondroitin-sulfuric 

 acid (cartilage ground substance), and amyloid. 



Choice of the aldehyde reagent. —SchiS's reagent gives 

 equally good results after any of the oxidants; silver solu- 

 tions are less specific and less reliable after periodate and 

 should be used only in combination with chromic acid. The 

 deep black shade may be an advantage in microphotography. 



Methods 



Oxidation with chromic acid.— Tresit sections for 40-60 

 minutes with a 4-5 per cent solution of chromic acid. Wash 

 under the tap for at least 5 minutes; the color of chromic acid 

 must be removed completely. 



Oxidation with periodic acid.— Tresit sections for about 10 

 minutes with a 0.25-0.5 per cent solution of periodic acid; 

 wash under the tap for 10 minutes. Hotchkiss^ originally rec- 

 ommended a rinse in bisulfite after oxidation. The eflFect of 

 this step will be a delayed and gradual development of color 

 in the next step. This may be a desirable feature if the aim 

 is a sharper differentiation between the more promptly re- 



36. Kligman, A. M., and Mescon, H.: J. Bact., 60:415, 1950; Kligman, 

 A. M., Mescon, H., and DeLamater, E. D.: Am. J. Clin. Path., 21:86, 1951. 



37. Morrison, R. W., and Hack, M. H.: Am. J. Path., 25:597, 1949. 



38. Lillie, R. D.: Anat. Rec, 108:239, 1950. 



39. Lee, C. S.: J. Nat. Cancer Inst., 11:339, 1950. 



40. Black-Schaffer, B.: Proc. Soc. Exper. Biol. & Med., 72:225, 1949. 



