AGRICULTURAL CHEMISTRY — AGROTECHNY. 409 



Identified in a supposedly pure preparation of gliadin but no trace of it was 

 found in zein. 



The influence of heat and chemicals on the starch grain, H. Kraemeb 

 {Orig. Commun. 8. Internat. Cong. Appl. Chem. [Washington and Hew Yorlc^, 

 n (1912), Sect. Villi), pp. 31-35).— A study of the starch grain with particular 

 reference to its structure and the effect of heat upon the polarization and the 

 structure of the granule. 



About the effect of removing' the male or female organs, or both, upon 

 the sugar formation in the stalks of maize and sugar sorghum, E. Heckel 

 (Compt. Rend. Acad. Sci. [Paris], 155 (1912), No. 16, pp. 686-690; abs. in 

 Chem. Ztg., 36 (1912), No. 66, Repert., p. 3U; Osterr. TJngar. Ztschr. Zucker- 

 indus. u. Landw., 42 (1913), No. 1, p. J7i).— During 1911 and 1912 tests were 

 conducted with maize and sugar sorghums with Stewart's method as used by 

 Doby (E. S. R., 24, p. 707) for increasing tbe sugar content. The factor espe- 

 cially noted was the effect produced as a result of removing the male or female 

 inflorescences, or both. The highest amount of saccharose was noted when both 

 elements were removed, the maximum quantity in the stalk (11.98 per cent in 

 maize juice and 13.7 per cent in sorghum juice) being nearly double that of 

 the uncobbed plants. 



Starch was found to be present to quite an extent in the stalks from which 

 either the female or the male and female flowers had been taken off. The 

 starch was noted as a sediment from the juice, and would no doubt interfere 

 materially with the defecating and crystallizing operation if these plants are 

 used for the manufacture of sugar commercially. The difficulties, however, may 

 be obviated, the author believes, by leaving a plant having one female inflor- 

 escence in the vicinity of plants which have had only their female flowers 

 removed. 



Some soluble substances (dextrin) which gave a red reaction with iodin were 

 also present in the juice. 



A new method for determining potassium titrametrically in fertilizers, 

 B. ScHMiTZ (Afts. in Chem. Ztg., 36 (1912), No. 88, p. 842).— A detailed descrip- 

 tion is given of the method, which depends upon the reduction of the potassium 

 platinic chlorid with alcohol in the presence of finely divided platinum. The 

 hydrochloric acid liberated is titrated by the usual methods. 



The soluble silicic acid in Thomas slag powder and its influence upon 

 the estimation of citric acid-soluble phosphoric acid, M. Popp (Abs. in Chem. 

 Ztg., 36 (1912), No. 115, pp. 1102, 1103).— It was noted that when using the 

 methods of Bottcher (E. S. R., 15, p. 744) and Wagner (B. S. R., 15, p. 645) for 

 citric acid-soluble phosphoric acid high results are often obtained (2 per cent 

 and higher) for phosphoric acid. This is explained by the fact that larger or 

 smaller amounts of silicic acid, which have been dissolved by the citric acid, are 

 precipitated. It is shown that the soluble silicic acid in Thomas slag is then 

 only precipitated when the slag contains a small amount of soluble iron. 



On the basis of some optical tests it is shown that the silicic acid soluble in 

 citric acid is not present in a colloidal state. It was also impossible to detect 

 colloidal silicic acid in the acid extracts by dialysis or by ultrafiltration. On the 

 other hand in the alkaline extracts obtained with ammonium citrate the silicic 

 acid was in a colloidal condition. 



If some ferric chlorid is added to such solutions, the silicic acid is not pre- 

 cipitated. No metals other than iron can keep the injurious silicic acid in solu- 

 tion and only then when the iron is used as an ion. 



A method is proposed for determining citric acid-soluble phosphoric acid based 

 on this principle. 



