AGRirULTURAT. ('TTEMTSTRY. 809 



ill iH'ot sugar it is cMHsidcrcd iinportaiit to staiHlar(liz(> the Fehling solufum 

 with a sulutioii ul" pure siK-rosc and invert sugar in the iiroitortions found 

 in tiie sample. If a elarified solution is used it is also eonsiden^d necessary 

 to clarify the standardizing solution before titration. When these precautions 

 are taken the volumetric method is believed to be capable of giving as accurate 

 results as the gravimetric method. 



The method of analysis of milk used in the government laboratory for 

 samples referred under the sale of food and drugs acts, H. D. Richmond and 

 K. II. :Mii.i.i:u (.W(f(///.^■^ .?/ (IHOd). \(). .i(!7. pp. .?/7-.J.?.T).— In the case of 

 fi'esli millv Hie luacer.-ilion nieUiod employe<l in llie govei-mneni lalioratory 

 is lielieved to give results which are accurate for fat, but slightly too high 

 for solids-not-fat. The higher results for the solids-not-fat are attributed 

 in part to the occurrence of sugar in th(> hydrated form and to the presence 

 of aldehyde in llie etlier. 



In 18 out of !"•• analyses of samiiles of sour millc the authors rejtort fair 

 agreement of Hie li^'ures for fat liy the maceration method with those ob- 

 tained by the (Jottlieb method on Llie fresh sanii)les. A consider;ible variation 

 ill the remaining sample was attributed to an unusual deconiiiosition. 



The main i)art of th(> pa])er deals with the corrections allowed for decompo- 

 sition products in cniculating the composition of the fresh milk when the 

 sample examined lins undergone fermentative changes. The method employed 

 in the government lal)oratory makes corrections -for alcohol, volatile acids, and 

 ammonia, and is believed to give results within 0.2 per cent of the truth 

 except in cases of high l)iityric fermentation or other abnormal decompo- 

 sition. The authors lielieve that certain small additional corrections may be 

 made with advantage and suggest allowance for lactic acid, butyric acid, 

 and the aldehyde taken up from the ether vised. 



The work, on the whole, indicates that the government laboratory method is 

 substantially accurate for the usual samples, but that special corrections 

 ought to b(> ai)plied in cases of unusual fermentations, two of which were 

 found by the authors in an examination of the li) samples. 



The refractometric determination of milk fat, F. Lowe {MilcJiir. Zeiithl.. 

 2 (1906), A'o. D. pp. '//'/-'//6').— Scales have been constructed for the Wollny 

 and Abbe refractometeis whereby the percentages of fat may be read directly. 



A modification of the salt method, Rusche (Molk. Ztg., 20 (1006), No. 38. 

 jip. 1075-1(117 ). — In jireliminary experiments the author obtained good results 

 by reducing the amount of salt required in the Gerber alkali method from 

 240 to 120 gm. per liter and increasing the amount of alcohol from 0.(5 to 



1 cc. This modi lica lion is ]»elieved to lessen the danger of saponifying the fat. 

 The determination of acidity in cream, Hesse-(}ustrow (Milcltir. ZeiithL, 



2 (1906), A'o. 9, pp. .'lis. 1,19). — In determining acidity by the Thorner method, 

 it is considered necessary to weigh 10 gm. of cream rather than to measure 

 10 cc. with a pipette. 



On the determination of fat in cheese, M. Weibull (Ztschr. I'litersuch. 

 Nahr. N. (IcHits.'^iiitl.. II {I'.iiiC). Xo. I.!, pp. 7.U)~73S). — Comparative tests of 

 the extraction, hydrocldoric acid, and Gottlieb methods were considered as 

 showing the superiority of tlie last-mentioned method for this purpose. 



Investigations on the determination of soluble and insoluble volatile 

 fatty acids, J. Delatte and J. LEcajAXD (/////. <sv>r. Vhhii. Beh/., 20 {19(i(!), A"o. 7. 

 pp. 230-23')). — The Reichert-Meissl number was found to increase from ;'.O.o:i 

 when saponification was completed in \ hour to 4().5."> when the period of sapon- 

 itication was prolonged to from 5 to 6 hours. This increase is considered 

 due to depolymerizatiou. Saponification for * hour is recommended. 



