MICROCHEMISTRY. 6g 



For Leptothrix ochracea Winogradsky (II, 268) has shown 

 by recent investigations that the iron is first deposited in 

 soluble form in the gelatinous envelopes, most probably as 

 a neutral ferric salt of an organic acid. This then gradually 

 passes over into a basic salt insoluble in water, and finally 

 into almost pure ferric hydroxide, which is transformed by 

 long submergence in water into a modification somewhat 

 less soluble in hydrochloric acid. 



B. Organic Compounds. 



I. FATTY SERIES 



i. Alcohols. 



Dulcite (Melampyrite] (C 6 H 8 (OH) 6 . 



103. Dulcite has been recognized by Borodin (I) by 

 adding one or a few drops of alcohol to sections of the plant 

 under investigation, covering with a cover-glass, and allow- 

 ing them to dry slowly. Dulcite then crystallizes in the 

 form of large prismatic or irregular flattened crystals which 

 may be distinguished from saltpeter and asparagin crystals 

 by being insoluble in a concentrated solution of dulcite and 

 by being transformed on heating to 190 C. into frothy dark 

 brown masses, with complete decomposition. Dulcite 

 crystals also differ from the very similar saltpeter crystals 

 in dissolving without color in diphenylamine-sulphuric acid 



(cf. 73)- 



Suitable objects for study are furnished by one-year-old 

 stems of Evonymus japonicus. 



author has recently shown (VIII) that the iron observed by him came from 

 the caustic potash used for the reaction, and that therefore the results ob- 

 tained by his method are untrustworthy. [Carl Miiller (I) has still more 

 recently concluded, not only that Molisch's proposed method is untrust- 

 worthy, but that his explanation of the source of the iron he found is 

 equally so. Miiller finds that the commercial hydroxide in stick form con- 

 tains no iron, and that the iron found in solutions of caustic potash comes 

 from the glass of the vessels in which they are contained. He believes also- 

 that the "masked" iron of Molisch is accumulated by plant specimens from 

 the glass vessels in which they are kept, and rejects Molisch's view that most 

 of the iron in the plant is organically combined.] 



