Oct 22. 1921 Acids of Pyrus coronaria, Rhus glabra, Etc. 227 



The figures from all the fractions are in excellent agreement with each 

 other and agree fairly well with malic acid. The results prove beyond 

 much doubt that only one acid is present in any quantity. Rogers {12), 

 the first to show the presence of calcium malate in berries of Rhus glabra, 

 did not attempt to prove that malic acid was the only one present, and 

 subsequent work was less careful than his. Although convinced by the 

 identity of the silver salts that nothing but malic acid was present in our 

 material, we felt that the determinations should be closer to the calcu- 

 lated value. The average of 13 determinations makes the percentage of 

 silver in the silver salt 61.85, whereas the theoretical value is 62.00 for 

 pure malic acid. We, therefore, prepared silver malate, using a Kahl- 

 baum preparation of the acid, and made four silver determinations in the 

 same manner in which our other determinations were made. The four 

 determinations gave us 61.94 P^^ cent, 61.92 per cent, 61.81 per cent, 

 and 61.91 per cent, averaging 61.89 per cent silver in pure silver malate 

 by our method of preparation and analysis. There can, therefore, 

 remain no doubt that the acid of sumac berries is all malic. 



MALIC ACID IN SUGAR-MAPLE SAP 



It is no new observation that mafic acid is present in the sap of the 

 sugar maple. Cowles (5), for example, has published methods for the 

 estimation of malic acid in maple products. Although it might have 

 been anticipated that the granular precipitate known as "maple sand" 

 which is deposited in the pans during the concentration of the sap would 

 prove to be calcium malate, no one, as far as we know, has previously 

 reported an analysis. Bloor (j) used "sugar sand" as a source of acid 

 in his work on the transformation of malic acid into sugar by the tissue 

 of the maple ^ but gave no data to bear out the natural and perhaps 

 quite justifiable inference that the acid was actually malic. Our sam- 

 ple was kindly obtained for us from Ohio, by Dr. Clinton A. Ludwig, 

 now of Clemson College, S. C. It was only necessary to add to the 

 "maple sand " sufficient hydrochloric acid to transform the crude calcium 

 malate into the acid calcium salt. The latter was obtained pure by 

 repeated boiling with animal charcoal and recrystallization from hot 

 water. It was neutralized with alkali, and silver nitrate was added to 

 precipitate the insoluble silver malate. Three separate analyses for 

 silver gave the following results : 



(i) 0.4129 gm. silver salt gave 0.2560 gm. Ag. 



(11) 0.1922 gm. silver salt gave 0.1190 gm. Ag. 



(ill) 0.2892 gm. silver salt gave 0.1796 gm. Ag. 



Calculated for C4H405Ag2; Ag, 62.00 per cent. 



Found: (i) 62.00 per cent; (11) 61.91 per cent; (iii) 62.10 per cent. 



1 It may be noted that Bloor used tissues of "Acer saccarinum " for his work. Since he gives no authority 

 for the name, one is left in doubt as to whether he means the silver maple (A. saccharinum L.) or the 

 sugar maple (,A. saccharum Marsh.; A. saccharinum Wang., not I,.). 



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