CHEMISTRY. 311 



cent sulphuric acid (sp. gr. 1.145), shaking frequently and cooling- to 

 prevent the loss of volatile fatty acids. The solution should contain 

 an excess of about 4.4 gin. sulphuric acid. When the solution is quite 

 clear add 50 cc. petroleum ether of good quality (sp. gr. 0.0 to 0.7, boil- 

 ing point about 60°), close the flask tightly and shake thoroughly 30 

 times at intervals of 1 to 2 minutes. The cork should not be removed, 

 since some of the petroleum ether would evaporate. Add sufficient 

 saturated sodium chlorid solution to make 290 cc, shake a few times, 

 and allow the flask to stand a short time in a cool place. The bottom 

 of the petroleum ether layer should be at the 240 cc. mark on the neck 

 of the flask. The petroleum ether will contain all the fatty acids in 

 solution. Remove 20 cc. with a suitable pipette, dilute with 40 cc. of 

 90 per cent alcohol, add 1 cc. of phenolphthalien and titrate with an 

 alcoholic solution of decinormal potassium hydroxid, noting the amount 

 required. Evaporate in a suitable vessel with a glass cover upon a 

 moderately warm water bath or in other convenient way, dry at 100° C. 

 and weigh with the cover on the dish, since the potassium salts of fatty 

 acids are hygroscopic. 



The amount of fat in the original material can be calculated with the 

 aid of the following formula : 



T _ j- S - 0-01 -(K* 0-00255) -] m 



F equals fat in original substance, S the weight of potassium salts 

 of fatty acid in 20 cc. of petroleum ether, K the amount of potassium 

 hydroxid solution used, and A the weight of the material taken. 



Modifications of the method are given for use in determining the 

 amount of fat in hay, flour, and grain, and comparisons of this method 

 with the Soxhlet method of extraction. The results show that the 

 method is accurate, and in the authors' opinion it can be recommended 

 as being more rapid than the ordinary methods. 



Determinations of fat by Liebermann's saponification method, 

 F. Tangl and J. Weiser (Arch. Physiol. [Pfliiger], 72 (1898), Ao. 7-8, 

 pp. 367-369). — The authors determined the fat in a number of samples 

 of meat and feces by the method described above and by Dormeyer's 

 method (E. S. It., 7, p. 919). Equally good results were obtained in 

 both cases. The first method is recommended as fully as accurate as 

 Dormeyer's and less time consuming. 



A simple method for the estimation of carbohydrates (sugar, 

 starch, dextrin) in foods and condiments, F. Grommes (Sitz- 

 ungsber. Phys.-med. Soc. Urlangen, 29 (1897), pp. 17-28, fig. J).— The 

 author describes Fleischer's apparatus and method for determining the 

 sugar content of foods and beverages. The apparatus is shown in 

 the accompanying figure (fig. 9). The method for determining sugar 

 in wine, beer, and other liquids is as follows: A sample of the liquid, 

 decolorized with animal charcoal (if this is necessary), is boiled with 



