Organic Substances 107 



acetone, sudanophilia ) of the lipid present at sites of keto- 

 steroid production is really specific for ketosteroids, no other 

 known type of substance displays the entire battery of reac- 

 tions. Chemical considerations are decidedly against this as- 

 sumption. In fresh tissues such reactions are entirely nega- 

 tive; on mere standing or after treatment with mild oxidants 

 they become increasingly positive— an indication that what- 

 ever gives the reaction must be the result of an oxidative 

 process. Ketosteroids would be expected to react directly, 

 even in fresh tissues. The distribution pattern of carbonyl 

 compounds as seen with the relatively aldehyde-specific 

 Schiff's reagent is invariably either identical with, or ex- 

 tremely similar to, that obtained by the use of *1<:etone rea- 

 gents," both in the endocrine organs and elsewhere^^ ( brain, 

 atherosclerotic plaques, necrotic tumors, etc.). The minor 

 discrepancies occasionally observed are theoretically readily 

 explainable by differences in the lipid solubility of the rea- 

 gents and possibly by differences in reactivity of the several 

 aldehydic substances present (steric factors?). Similar dif- 

 ferences in reactivity have been reported in the cases of such 

 relatively homogeneous groups of substances as desoxyribose- 

 nucleic acids^^ and mucopolysaccharides,^^ even though the 

 reactive groups within each class are the same. 



In a series of recent papers^^ Seligman and his group re- 

 ported their studies on the carbonyl groups of formalin-fixed 

 nervous tissue, adrenals, and testes, demonstrated by the 

 2-hydroxy-3-naphthoic acid hydrazide-Blue B Salt method. 

 They came to the conclusion that the reacting carbonyl 

 groups, "unmasked" by formalin, are of a ketonic rather than 



66. Gomori, G.: Proc. Soc. Exper. Biol. & Med., 51:133, 1942. 



67. Lessler, M. A., and Kopac, M. J.: Anat. Rec, 108:578, 1950. 



68. Monne, L., and Slautterback, D. B.: Exper. Cell Research, 1:477, 

 1950. 



69. Ashbel, R., and Seligman, A. M.: Endocrinology, 44:565, 1949; 

 Seligman, A. M., and Ashbel, R.: Cancer, 4:579, 1951; Seligman, A. M., 

 and Ashbel, R.: Endocrinology, 49:110, 1951; Ashbel, R., Cohen, R. B., and 

 Seligman, A. M.: Endocrinology, 49:265, 1951; Rabinovici, N.: Endocri- 

 nology, 49:579, 1951. 



