238 



THE ALUMNI JOURNAL. 



lactose the color is produced only when the 

 mixture is boiled with the hydrochloric acid 

 and allowed to cool. Compare Baudouin's test- 

 Baudouin's test for sesame oil. The reagent 

 consists of o.i grain sugar dissolved in lo ccm. 

 hydrochloric acid, specific gravity 1.18. One 

 volume of this solution is shaken with 2 volumes 

 of the oil to be tested. If sesame oil is present 

 the oil upon separation is cherry red. 



According to Lewin, the reaction is carried 

 out as follows: 0.5 grains of finely pulverized 

 sugar in a test tube is covered with 2 ccm. of 

 the oil, then i ccm. of hydrochloric acid, spe- 

 cific gravity 1.18, is poured carefully down the 

 sides of the tube. If sesame oil is present a 

 rose-red zone is formed within i to 5 minutes. 



According to Dlillian, Baudouin's test is more 

 delicate when carried out with the well dried 

 free fatty acids, which have been obtained from 

 the oil. 



Villavecchia and Fabris (q v.) replace sugar 

 and hydrochloric acid by furfurol. Compare 

 also Carlinfanti and Gassend, 



Baumann's reagent for polyatomic alcohols 

 and diamines is benzoylchloride added to the 

 solution of the alcohol or amine in aqueous so- 

 da. Insoluble benzoyl esters are precipitated. 

 Used for the detection of glycerin, carbohydrates 

 and various products of bacterial activity in 

 urine. 



Bayer's reaction for indol. A solution of in- 

 dol yields upon the addition of dilute nitric 

 acid and dilute solution of potassium nitrite so- 

 lution a red color or precipitate. 



Beale's creosote mixture for imbedding mi- 

 croscopic preparations. To a solution of 180 g. 

 methyl alcohol and 11 g. creosote suflBcient 

 chalk is added to make a thick paste. While 

 constantly stirring 1920 g. of water are grad- 

 ually added, then a few fragments of camphor. 

 After standing several weeks the mixture is fil- 

 tered. 



Bechi's test for cottonseed oil. Upon heating 

 with an alcoholic-ethereal silver nitrate solution 

 cottonseed oil (eventually upon addition of col- 

 za oil) yields a reddish brown color; olive oil 

 and other oils remain uncolored. The Swiss 

 Society for Analytical Chemists in 1895 sug- 

 gested the following reagent: to i g. silver 

 nitrate, dissolved in 5 ccm. of water, 200 ccm. 

 alcohol, 20 ccm ether and i ccm. nitric acid, 

 specific gravity i .4, are added. In order to test 

 for cottonseed oil, 10 ccm. of the fat and 3 ccm. 

 of the reagent are mixed and the mixture heat- 

 ed on a boiling water-bath for 10 minutes. If 

 cottonseed oil is present the mixture becomes 



brown or even black. Compare Millian' s reac- 

 tion. 



Becker's reaction for picrotoxine. The alka- 

 loid reduces Fehling's solution when gentle 

 heat is applied. 



Behren's test for fatty oils. When treated 

 with a mixture of equal parts of sulphuric acid, 

 specific gravity 1.835 to i-84, and nitric acid, 

 specific gravity 1.3, different oils show different 

 behavior. Sesame oil produces a green color. 

 Beissenhirtz's reaction for aniline. If to a 

 solution of aniline in concentrated sulphuric 

 acid a grain of potassium bichromate is added, 

 the solution first becomes red, then blue, the 

 color gradually disappearing. 



Berthelot's alcohol reaction. If a dilute so- 

 lution of alcohol is shaken with a few drops of 

 benzovl chloride and soda solution until the 

 odor of benzoyl chloride disappears, the pecu- 

 liar odor of ethyl benzoate is formed. 



Berzelius' test for albumen. Metaphosphoric 

 acid in freshly prepared concentrated solution 

 precipitates all albuminous substances (except 

 peptone) from their aqueous solutions. 



Bettendorf's test for arsenic. A solution of 

 stannous chloride in concentrated hydrochloric 

 acid, specific gravity 1.19, when heated with a 

 solution of arsenic or arsenous acids in strong 

 hydrochloric acid, yields a brownish turbidity 

 or precipitate of metallic arsenic and tin. The 

 presence of much sulphuric acid, of oxydizing 

 or organic substances interfere with the reac- 

 tion. 



Bieber's reagent consists of equal parts of con- 

 centrated sulphuric acid, red nitric acid and 

 water. 



Biel's cocaine test. If a solution of o.i g. 

 cocaine salt in i ccm. concentrated sulphuric 

 acid is heated for several minutes on a water- 

 bath, the addition of several cubic centimeters 

 of water causes the formation of a white, crys- 

 talline precipitate of benzoic acid. 



Biltz's test for mono- and bicarbonate of so- 

 dium. When treated with mercuric chloride 

 under certain conditions, these yield a white or 

 respectively a brown precipitate. 



Bischoff's reaction for gallic acid. When 

 heated with dilute sulphuric acid and cane su- 

 gar gallic acid produces a red coloration. See 

 also Pettenkofer, Strassbiitg. 



Bischoff's melting point test for butter. See 

 DrouoVs test. 



Boas' reagent is a solution of tropaeolin, or 

 paper saturated with such solution. 



Bodde's reaction for the distinction between 

 resorcin and phenol, benzoic acid and salicylic 



