RECENT WORK IN AGRICULTURAL SCIENCE. 



CHEMISTRY. 



A contribution to the method of extracting fat, E. Voit (Ztschr. 

 Biol, 35 (1897), No. 4, pp. 555-582). — It has been claimed that the 

 method of determining- fat in meat by extraction with ether does not 

 give accurate results. The author reports in detail the ether-extraction 

 method ordinarily followed at Munich which he believes to be reason- 

 ably accurate. This differs in some points from that in use elsewhere. 

 It is as follows: Duplicate samples of meat are dried on a water bath 

 at a temperature under 80° C. The substance thus dried often absorbs 

 water when pulverized, therefore it is treated with sufficient alcohol to 

 render it crummy and then dried until the odor of alcohol is no longer 

 noticeable. After standing fin- some time covered but accessible to the 

 air it is pulverized. Samples of the material thus prepared are used 

 for further analysis. 



A number of experiments were made by Krummacher to test the 

 accuracy of this method as compared with the digestion method of 

 estimating fats as proposed by Dormeyer (E. S. R., 7, p. 919). The con- 

 clusion was reached that when the extraction with ether was properly 

 carried out with small quantities of substance as free from water as 

 possible 21 hours extraction was sufficient. In the majority of cases 

 extraction with ether alone removed all the fat. It is certain that 95 

 per cent of the fat may be so obtained, and this method may be used 

 unless greater accuracy is desired. There are still sources of error in 

 the method of extraction by ether which are not understood. 



On the determination of fat and casein in feces, H. Poole 

 {Jour. Amer. Ghent. Soc, 19 (1897), Xo. 11, pp. 877-881). — In connection 

 with the study of the feces of' a child fed an exclusive milk diet the 

 author proposes tentatively the following method of determining the 

 fat and casein. The ether extract of the dried feces, which contains 

 both fat and cholesterol, is evaporated until nearly dry at 100° and 

 then heated to 110° until dry. It is then saponified with alcoholic pot- 

 ash, water added, and the mixture boiled to expel the alcohol. The 

 filtered solution, which should be clear and opalescent, is extracted 

 with ether several times to remove the cholesterol. The aqueous solu- 

 tion is evaporated until nearly dry and then taken up with water, the 

 fatty acid being determined by any of the usual methods. 



