CHEMISTRY. 649 



New reactions for disting-uishing- raw and heated milk, as w^ell as for the 

 detection of hydrogen peroxid in milk, C. Arnold and C. Mentsel {Ztschr. 

 Uiiterttuch. Xdhr. u. (h'tuisxintl., 6' {1903), No. 12, pp. 64S, 549). — Characteristic color 

 reactions arc reported as o])tained ])y 2 aromatic amins, p-diethyl-p-phenylenediamin 

 and p-diamido-diphenylaniinhydi'ochlorid. 



The examination of milk samples containing unduly large quantities of 

 preservatives, M. Siegfeld {Ztschr. Vidermcli. Nahr. u. (lenuxxmtl., 6 {1903), No. 

 9, pp. 397-408). — Fat was determined by the Gerber method in milk containing var- 

 ious Cjuantities of formalin and potassium bicliromate. The results were materially 

 influenced by large quantities of these preservatives. 



A comparative study of methods of determining formaldehyde, B. H. Smith 

 {Jouv. Amcr. Chem. Soc, -25 {1903), No. 10, pp. 1028-1035).— The Blank and Fink- 

 enbeiner method of determining formaldehyde was found very satisfactory for strong 

 solutions. The Legler method gave lower results but was fairly satisfactory. The 

 gravimetric hexamethylenetetramin method was considered practically worthless. 

 The iodiometric and potassium cyanid methods gave good results on dilute solutions. 

 It was considered possible to determine with accuracy 1 part of formaldehyde in 

 100,000 by the potassium cyanid method. In the anilin volumetric method the 

 author found it impossible to ascertain the end point. 



The estimation of formaldehyde in milk, B. H. Smith {.Tour. Amer. Chem. 

 Soc, 25 {1903), No. 10, pp. 1036-1038, dgm. 1) . — Several experiments a.re reported, 

 the results of which are summarized by the author as follows: 



"It may be said that considerable time and trouble may be saved by using a 

 Kjeldahl flask and a round, flat evaporating burner in the distillation of milk; that 

 the quantity of suli^huric acid added has a decided effect upon the amount of formal- 

 dehyde obtained in the first part of the distillation; that, if the treated milk is kept 

 in a cool place, the percentage of formaldehyde found will remain practically con- 

 stant for at least 48 hours; and that where 100 cc. of milk are treated with 1 cc. of 

 sulphuric acid of a dilution 1:3 and distilled, the first 20 cc. of the distillate will con- 

 tain very close to 33 J per cent of the total formaldehyde present." 



A chemical method for detecting and measuring the addition of low-grade 

 jSour to wheat flour, G. Volpixo {(rior. Farm e Cliim., 52 {1903), pip. 337-346; abs. 

 in Chem. CenthL, 1903, II, No. 15, p. 844)- — Contrary to the opinion of other investi- 

 gators the author maintains that when a mixture of wheat flour and barley, rye, 

 maize, or rice meal is washed out with water by means of a water pump, only gluten 

 possessing the qualities of wheat gluten will remain, and in about the proportion 

 in which wheat gluten is present in the original mixture. The insoluble proteids 

 of barley, rye, maize, and rice meal are found in the water used for washing the 

 gluten, and are removed from the water by filtration. The estimation by the 

 Kjeldahl method of these insoluble proteids obtained after the removal of gluten 

 furnishes information regarding the quality of the flour and the kind and amount of 

 adulteration. 



Flour is regarded as adulterated which contains, after the removal of the gluten, 

 more than 0.02 gm. of proteid insoluble in water. The kind of adulteration can be 

 determined usually with a microscope. Spoiled wheat flour shows an increase in 

 the insoluble proteids remaining after removing gluten which is proportional to the 

 degree of change. These insoluble bodies do not equal the amount found in other 

 sorts of flour besides wheat. 



Volumetric determinations, A. Wohl {Ber. Deut. Chem. GeselL, 36 {1903), pp. 

 1417-1422; ahs. in Bid. Sor. Chim. Paris, 3. ser., 30 {1903), No. 22, p. 1230) .—The author 

 explains the application of his method, previously described (E. S. R., 14, p. 1043), to 

 the determination of ammonia and carl)on dioxid. 



Potassium tetroxalate as a titrating reagent, O. KtJHLiNG {Ztschr. Angew. 

 Chem., 16, {1903), pp. 1030-1033; abs. in Chem. CenthL, 1903, II, No. 25, pp. 1390, 



