CHEMISTRY. 



107 



with oleic acid there is also formed a deposit 

 insoluble in alcohol. If a thin layer of the 

 falsified oleic acid is placed upon a slip of lead, 

 scraped clean, and some pure oleic acid is placed 

 upon a similar slip of lead for comparison, the 

 impure acid will, on the next day, be more or 

 less resinified, while the pure acid will be hardly 

 altered. If some drops of falsified oleic acid are 

 mixed with an equal volume of soda-lye, an in- 

 tense yellow color is produced, while pure oleic 

 acid, similarly treated, merely takes a grayish 

 tint. 



For the detection of tin in minerals, Alexan- 

 der Johnstone cuts out the small beads of metal 

 which settle to the bottom of the assay on treat- 

 ment with the white flux or fusion mixture of 

 Fresenius ; and having pulverized it and washed 

 it, treats the remaining silver-like malleable 

 scales of metal with boiling concentrated hydro- 

 chloric acid and solution of gold chloride. If 

 the white scales are wholly or partly composed 

 of tin, the bottom of the mortar will receive a 

 distinct purple stain by the formation of the 

 purple of Cassius. As an additional test, a cur- 

 rent of sulphuretted hydrogen may be projected 

 upon the moist stained bottom of the mortar, 

 when a skin of brown stannous sulphuride will 

 be formed. 



Chemical Synthesis. Prof. Emil Fisher's 

 researches on the sugars of the glucose group 

 have been remarkably successful. Several months 

 ago he prepared a new synthetical sugar, which 

 he called acrose, and found to be an isomer of 

 dextrose and levulose. He has now succeeded in 

 determining the constitution of acrose, and has 

 shown that it is the inactive modification of 

 levulose. He has also effected the synthesis of 

 levulose ; has discovered the inactive and the 

 levo-modifications of mannite and of the new 

 sugar mannose; has shown that mannose and 

 dextrose have the same constitution, and that 

 one may be converted into the other ; has pre- 

 pared all these substances synthetically ; and 

 has developed and perfected the methods of 

 transforming the sugars and their derivatives 

 into one another to such an extent that the syn- 

 thesis of the remaining members of the glucose 

 group will probably be effected in the near 

 future. 



The synthesis of indigo from monobromace- 

 tanilide,'by W. Flimm, is the first that has been 

 accomplished from a mono-substitution product 

 of benzol. If monobromacetanilide is melted 

 with dry caustic alkali, a fused mass is obtained, 

 the solution of which in water soon turns blue 

 and separates indigo ; aniline and isocyanophenyl 

 are also formed. The yield is small, being not 

 more than 4 per cent, of the anilide used. 



Urea chloride has been used by Gattermann, 

 Schmidt, and Harris, reacting with aromatic 

 hydrocarbons and phenylethers in the presence 

 of aluminum chloride to effect the synthesis of 

 carbo acids. The urea chloride was formed from 

 phosgene and ammonium chloride. The method 

 is inconvenient, on account of the large quanti- 

 ties of liquid phosgene it requires. To avoid 

 this inconvenience, L. Gattermann and A. Rosso- 

 lymo use cyanic acid and hydrochloric acid, two 

 substances into which urea chloride dissociates 

 at the high temperatures at which the syntheses 

 are performed. 



Pyrazol, 03^^".,, the fundamental base of a 

 rapidly growing series of compounds, has been 

 synthesized by Prof. Balbiano, of Messina, from 

 epichlorhydrin and the recently isolated hydra- 

 zin hydrate. It is obtained as a mass of hard, 

 colorless needles. The crystals are readily solu- 

 ble in cold water, with production of neutral 

 solution, possess an odor similar to that of pyri- 

 dine, melt into a colorless liquid at from 65-5 

 to 70, while the liquid boils at from 186 to 

 188 C. 



Organic Chemistry. The gums yield, when 

 subjected to hydrolytic action, glucose-like bod- 

 ies which, when carefully studied, have usually 

 been identified as either galactose or arabinose. 

 Gum arabic sometimes yields galactose and some- 

 times arabinose, but it is not clear whether this 

 is a specific characteristic of a distinct gum, or 

 whether there may not be gums of different 

 origins sold under the one name. The gum 

 exuding from the bark of a cherry tree and 

 tragacanth gum yield arabinose. The mucilage 

 occurring in the seed coats of linseed, quince 

 seeds, etc., yields glucoses which have not been 

 satisfactorily identified. A gum-like substance 

 which can be extracted from liquefied tissues by 

 alkalies yields xylose. The gum exuding from 

 the bark" and the fruit of peach trees has been ex- 

 amined by W. E. Stone. That from the fruit was 

 much the clearer in color and the purer. It 

 is soluble in water, by which it is first swollen 

 to a marked degree, and in solution it showed 

 a slightly acid reaction and a distinct, al- 

 though not strong, laevo-rotation. The results 

 of the first steps in the analysis indicated the 

 presence of those substances which yield arabi- 

 nose and galactose on hydrolysis. The contin- 

 ued investigation for the purpose of isolating 

 and identifying these substances gave, from the 

 bark gum, two products one with specific ro- 

 tation 102-3, which approximated closely to that 

 of arabinose (104), and a second with a specific 

 rotation 82'09% which is practically that of glu- 

 cose. Two products identical with these were also 

 obtained from the fruit gum. This analysis 

 was confirmed by further tests. 



In a paper on " The Occurrence of the Penta- 

 glucoses," read in the American Association, the 

 same author reported concerning his examina- 

 tions of forty vegetable products, selected with a 

 view of obtaining as great a variety as possible 

 for the detection of arabinose and xylose. In 

 thirty-two of these substances from 1 to 12 per 

 cent, of the pentaglucoses, or bodies from which 

 they are derived, were recognized. They were 

 even found in the excrement of domestic ani- 

 mals, showing the operation of some degree of 

 digestive action there. The existence of a class 

 of compounds not commonly recognized in foods 

 is indicated. In another paper by Prof. Stone 

 arabinose was found to have a stronger reducing 

 effect upon Fehling's solution than any other 

 known sugar. A third paper by the same au- 

 thor developed a method for the quantitative 

 determination of pentaglucoses in food stuffs. 



In the analysis of seeds, all that part of their 

 non-nitrogenous constituents which is soluble in 

 water, and which upon boiling with a dilute 

 acid becomes converted into bodies capable of 

 reducing an alkali-copper solution, has been ex- 

 pressed as dextrine. W. Maxwell considers that 



