AGEICULTUEAL CHEMISTRY AGKOTECHNY. 507 



(€22). were compared, and all of these were decolorized by sodium sulphite 

 with the exception of parafuchsiu and the new fuchsia, which were only partly 

 decolorized. The color of none of the dyes was affected by the addition of acid. 

 Fuchsin (C20) is the preferi'ed reagent. 



Formaldehyde is tested for directly in the distillate from the food and 

 especially in the first runnings, providing that it is not in a fixed state. In 

 milk or colorless substances the reaction can be made without previous distil- 

 lation. Strongly colored solutions, such as wines and fruit jams, must first 

 be decolorized with animal charcoal. The diminution of formaldehyde in food 

 is said to be due either to fixation or to decomposition by micro-organisms. 

 The extent of formaldehyde fixation is shown by the fact that rhubarb leaves 

 having an addition of 1 : 10,000 when heated for an hour at 100° 0. give no 

 reaction for the substance. 



Formaldehyde may be converted into liexamethylentetramin and methylal. 

 Urine and urea fix formaldehyde very easily while milk fixes it only slightly. As 

 hexamethyleutetramin reacts only slightly at the beginning with fuchsin-sul- 

 phurous-hydrochloric acid, it is advisable to heat 10 parts of the solution with 

 'from 1 to 2 parts of hydrochloric acid on a water bath. 



The detection of formaldehyde-sulphurous acid is also considered. 



About the utility of vacuum distilling' methods for detecting formic acid, 

 T. Meul {Ztschr. Untcrsuch. Kahr. u. GcnussmU., 27 {1914), Xo. 10, pp. 733- 

 743). — This work deals especially with the separation of formic acid from acid 

 sugar-containing fluids. It indicates that it is possible, by observing the speci- 

 fications set down by Fincke (see above), to obtain the formic acid from such 

 fluids without the formation of acid during the distillation process under dimin- 

 ished pressure. The apparatus employed was Anschiitz and Reitter's. 



The preliminary work was done with solutions of formic acid ; formic and tar- 

 taric acids; formic acid and saccharose; formic acid, glucose, and tartaric acid; 

 levulose ; levulose and tartaric acid ; invert sugar and saccharose ; saccharose 

 and tartaric acid; saccharose and phosphoric acid; and saccharose, phosphoric 

 acid, anu tartaric acid. Although vei*y small amounts of formic acid were found 

 in the case of sugar solutions containing tartaric, phosphoric, or no acids, with 

 the ordinary vacuum distillation process it usually originated from impurities 

 present in the sugar. The steam vacuum method has a greater tendency to 

 form formic acid than the other methods. 



Tests were also made with authentic samples of honey which had been ana- 

 lyzed previously by Fincke's procedure. Distillates from the head, thorax, and 

 abdomen of bees (Apis mcUifcra) showed formic acid to be present in traces. A 

 few distillation tests with benzoic, salicylic, and ciuuamic acids led the author to 

 conclude that the steam distillation method is preferable to the shaking-out 

 method in the detection of preservatives. 



Determination of formic acid in ketchup, C. A. Peters and L. P. Howard 

 {Jour. Inclus. and Engin. Chcm., 7 {1915), No. 1, pp. 55-37).— This gives the 

 details of a study made for the purpose of adapting the Fincke method 

 (E. S. R., 20, p. 312), to the determination of formic acid in ketchup with the 

 apparatus described. From 91 to 92 per cent of the total formic acid added to 

 ketchup maj- be recovered in one and a half hours providing about 1,000 cc. of 

 distillate is passed over. 



The .unsaponifi^ability of m^owrah fat and its signifi.cance for the detection 

 of mowrah fat in edible animal and plant fats, P. Berg and J. Angerhausen 

 {Ztschr. Untcrsuch. Nahr. u. Genussmtl., 27 {1914), No. 10, pp. 723-731).— 

 Mowrah fat is one of the raw materials used in the margarin industry. It has 

 the consi.stency of American lard, and since its quality has been improved it is 



87235°— 15 2 



