\<.i:i< ilti RAL 0HEMI81 81 . 



nia" by recent investigations and the greatl) increased importance of biological and 

 physical examination, the last rendered necessary by recent progress in methods of 

 precipitation, sedimentation, and water softening. 



A bibliography is given containing "a list of references to the works moe 

 Baited in America, arranged for the purpose of assisting the reader in getting in touch 

 with the genera] aspects of a method, including its historj and application, together 

 with full technical details of the procedure as now practiced. 



"No attempt is made to report upon the interpretation of the results of water 

 analyses or upon the classification of bacteria, as these subjects are receiving the 

 attention of other committees of the association." 



Progress in the chemistry of waters, including- natural and artificial min- 

 eral waters, A. Goldberg [Chem. Ztg., 29 (1905), No. 70, /</<. 915 921). \ brief 

 review of investigations relating to this subject, with numerous references to 

 literature. 



The volumetric determination of reducing sugars, A. K. Ling and T. Rkndi i. 

 (Analyst, SO (1905 . No. S51, />/>. 182-190). — Ferrous thiocyanate has been found by 

 the authors the most satisfactory indicator for titrating BUgars with Fehling's solution. 



The indicator is prepared by dissolving l gm. <>f ferrous ammonium sulphate and 

 1 gm. <>f ammonium thiocyanate in lu ce. of water at a temperature of about 45 to 

 50° (\, cooling the solution, and adding 50 cc. of concentrated hydrochloric acid. 

 The solution is decolorized by the addition of a little zinc < lust. The Fehling's solu- 

 tion is not diluted. The sugar solution should he of such a strength that 20 to 30 ce. 

 will reduce lo ce. of Fehling's solution. 



A study of the hydrogen peroxid method of determining formaldehyde, 

 .1. K. Haywood and B. H. Smith (Jour. Amer. Chem. Soc, 91 (1905), No.9,pp. i 

 1188). — The methods of Blank and Finkenbeiher and of Fresenius and Grunhul 

 served as a hasis for the tests reported. A modified procedure for carrying out the 

 former method is suggested. 



A new method for the detection of formalin in milk, Otz ( Chem. Ztg., 99 

 (1905), No. /'.'', p. 669). — Unless added to milk in larger quantities than are q< 

 sary for the purposes of preservation, formaldehyde was not found to interfere with 

 the tests used to distinguish boiled from raw milk. 



Winckel's test for enzyms was found very delicate for detecting formaldehyde in 

 milk. Equal parts of milk and hydrochloric acid, sp. gr. 1.1'.'. are heated with a 

 crystal of vanillin, when a violet or raspberry color shows the pre-, nee of formalde- 

 hyde, a faint trace, however, being indicated by a yellow color. The author found 

 that piperonal or p-oxybenzaldehyde could besubstituted for the vanillin, though not 

 with quite so satisfactory results. This method of detecting formaldehyde was not 

 found applicable to other food products than milk. 



New method of rapid milk analysis, F. Bordas and Touplain Ann. ('him. 

 Analyt., 10 (1905), No. 7, pp. 967, 968; Rev. Soc. Sci. Hyg. Aliment., 8 1905), & 

 pp. 168-168). — Ten cc. of milk is added drop by drop to 25 v. of 65 per cent alcohol 

 acidified by acetic acid in a weighed sedimentation tube. After standing for a few 

 moments this is centrifuged, the supernatant liquid decanted, and the precipitate 

 washed twice in 50 per cent alcohol, using ::•» cc for this purpose. 



Lactose is determined in the liquid obtained by mean- of Fehling's solution. Fat 

 is determined by extracting the precipitate with alcohol and ether, centrifuging, and 

 again extracting with ether, the decanted liquids being collected in a tared dish, 

 evaporated, and the fat weighed. The casein remaining in a tine powder in the 

 original sedimentation tube is then dried and weighed, after which it i- incinerated 

 and the ash determined. 



New method of milk analysis, J. Bkllibr (Ann. chlm. Analyt., 10(1905), No.7, 

 p/>. 968-276). — In the gravimetric method described the absorbent material used is 

 a medium fine sponge previously cut into small pieces and prepared by treating 



