Organic Substances 67 



43-45 



(hyaluronidase, pectinase, polygalacturonidase, etc.). 

 Hyaluronidase appears to be specific in abolishing some or 

 all staining reactions (depending on the source of the en- 

 zyme and on the length of exposure ) due to hyaluronic acid 

 and to chondroitin;*^ the limits of specificity of the other 

 enzymes remain to be established. 



B ) Methods for individual members of the group.— 

 a) Glycogen and starch.— The oldest method for starch is 

 the staining by iodine;*^ it is mentioned as early as 1825.^^ 

 Glycogen will stain in a mahogany brown, native starch in 

 dark blue. Iodine can be applied in the form of Lugol's solu- 

 tion,^^ iodine vapor, or a solution of iodine in parafiin oil.^^ 

 The iodine reaction is not absolutely specific; amyloid, some 

 protein substances, and lecithin^^ will also stain. Galactogen 

 does not stain.^^ The degree of contrast obtained is not too 

 high, and the preparations are not stable. Although some 

 workers still use it extensively, the iodine reaction can be 

 said to have little more than a historical interest. 



Best's carmine. ^'^— This is a purely empirical but highly se- 

 lective stain. Besides glycogen, it may stain mast cell gran- 

 ules, mucin, and fibrin, but in so much lighter shades that 

 confusion is unlikely. 



43. Hale, C. W.: Nature, 157:802, 1946. 



44. Grishman, E.: Bull. Intemat. A. M. Mus., 28:104, 1948. 



45. Gersh, L, and Catchpole, H. R.: Am. J. Anat., 85:457, 1949; Stough- 

 ton, R., and Wells, G.: J. Invest. Dermat., 14:37, 1950; McManus, J. F. A., 

 and Saunders, J. C.: Science, 111:204, 1950; McManus, J. F. A.: Am. J. 

 Path., 26:690, 1950; Bunting, H.: Ann. New York Acad. Sc, 52:977, 1950. 



46. Mathews, M. B., Roseman, S., and Dorfman, A.: J. Biol. Chem., 

 188:327, 1951. 



47. Mancini, R. E.: J. Nat. Cancer Inst., 10:1371, 1950; Gage, S. H.: 

 Tr. Am. Micr. Soc, 28:203, 1906. 



48. Caventou, J. B.: Ann. de chim. et de phys., 31:337, 1826. 



49. Langhans, T.: Virchows Arch. f. path. Anat., 120:28, 1890. 



50. Mancini, R. E., and Celani-Barry, R.: Rev. Soc. argent, de biol., 

 19:493, 1943; Mancini, R. E.: Medicina, 7:327, 1947; Mancini, R. E.: 

 Anat. Rec, 101 : 149, 1948. 



51. Romieu, M.: Compt. rend. Soc. de biol., 96:1230, 1927. 



52. Grainger, J. N. R., and Shillitoe, A. J.: Stain Technol., 27:81, 1952, 



