506 EXPERIMENT STATION EECOKD. 



these products. The various sources of flour are considered and photomicro- 

 graphs are included. 



The rapid determination of boric acid normally present in foods, or ex- 

 traneous boric acid, G. Bertrand and II. Agulhon (Ann. Falsif., 7 il91-i). 

 No. 65, pp. 119-121). — With a colorimetric method devised by the authors it is 

 possible to estimate quantitatively and easily small amounts of boric acid 

 in foods with sufficient accuracy to determine whether the boric acid was 

 present normally or had been added as a preservative. This is demonstrated, 

 by giving the results of an examination of a large variety of substances, in- 

 cluding fruits, vegetables, cereals, meats, eggs, and milk. 



Detection of formaldehyde in foods, F. Rachel {Pharm. Zentralhalle, 54 

 {1913), iNo. 31, pp. 759-761; ahs. in Jour. Cheni. Soc. [London'], lOJf. (1913), No. 

 612, II, p. 891). — Utilizing the suggestion made by Friese, the following process 

 for the detection of formaldehyde in meat, caviar, and fish is recommended : 



Acidify the substance with phosphoric acid, heat in a current of steam, and 

 mix 1 to 2 cc. of distillate with 4 cc. of milk free from formaldehyde and 10 cc. 

 of hydrochloric acid (sp. gr. 1.19) to which has been added 1 drop of nitric 

 acid per 300 cc. When formaldehyde is present a bluish-violet coloration ap- 

 pears. Colors appearing after five minutes are taken as a negative result. 

 When much formaldehyde is present milk does not give the reaction and the 

 experiment must be repeated with pure water. 



Detection and estimation of formic acid, H. Fincke (Biochem. Ztschr., 51 

 {1913), No. 4, pp. 253-287, figs. 2).— The first part of this paper deals with the 

 occurrence of formic acid, and the second with the reactions which were found 

 useful in Its qualitative and quantitative determination. Some of the quantita- 

 tive methods are given with much detail. 



The detection of formaldehyde in plants, H. Fincke {Biochem. Ztschr., 52 

 {1913), No. 3-4, pp. 214-225; abs. in Jour. Chem. 8oc. [Landon], 104 {1913), 

 No. 610, I, p. 947). — "For these researches [see also above] the Grosse-Bohle 

 reagent for the detection of formaldehyde was employed. This consists of a 

 rosanilin salt in the presence of sulphites and free hydrochloric acid, and is 

 to be distinguished from the ordinary magenta-sulphite solution for detection 

 of aldehydes, by the presence of free mineral acid. It was found by the author 

 to be capable of detecting formaldehyde in the dilution 1 : 500,000, giving with 

 the aldehyde a violet color. In numerous experiments on plants no indication 

 of the presence of formaldehyde was obtained with the use of this reagent ; 

 furthermore, formaldehyde could not be detected by the reagent after addition 

 to certain living plants. 



" The author draws the conclusion that his investigations throw no light on 

 the correctness or otherwise of Bayer's assimilation hjTiothesis." 



About the detection of small amounts of formaldehyde and some formal- 

 dehyde compounds with fuchsin-sulphurous-hydrochloric acid, H. Fincke 

 {Ztschr. Untersuch. Nahr. u. Genussmtl, 27 {1914), No. 1-3, pp. 246-253).— 

 As formaldehyde is decomposed under certain conditions it is essential to know 

 to what extent it occurred in foods. After repeating some of the work noted 

 above, the author lays stress upon the fact that the fuchsin-sulphurous-hydro- 

 chloric acid test is less influenced by other substances than any of the other 

 reagents used for detecting formaldehyde and consequently should find a wider 

 field of application. The reaction differentiates itself from the usual aldehyde 

 test by the fact that it is conducted in a medium containing an excess of free 

 acid. 



Attempts to substitute for rosolic acid similar coloring matters (highly 

 methylated fuchsin, acid fuchsin, and acid violet) were unsuccessful. The f neb- 

 cin hoijjologues, parafucbsiu (Cio), fuchsin (do), fuchsin (C-2i), and new fuchsin 



