TEST 



529 



TEST 



bot's Reagent for Fatty Oils is fuming nitric acid. 

 Different oils when mixed with this reagent show 

 different behavior with regard to coloration and solidi- 

 fication. Olive oil, e. g., yields a white (not red nor 

 brown) mixture which solidifies after one or two hours. 

 Barral's Test for Bile Pigments and Albumin in 

 Urine. Cover the urine in a test-tube with a stratum 

 of a 20% solution of aseptol (orthophenosulfonie 

 acid) and in the presence of albumin a white ring will 

 form at the zone of contact of the two fluids. It is 

 possible by this method to trace ' s ofa grain of albu- 

 min in I liter of urine. Mucin causes a similar pre- 

 cipitate, but this disappears on boiling. The presence 

 of bile-pigments will be indicated by the formation of a 

 green ring. This is much more sensitive than the 

 color test made with fuming nitric acid. Basoletto's 

 Reagent for Sesame Oil. A mixture of equal parts 

 by volume of sesame oil and a 2% solution of cane- 

 sugar in hydrochloric acid of specific gravity 1.124 is 

 colored red in the cold, but more rapidly upon heating. 

 With glucose and lactose the coloration is formed only 

 when the mixture is boiled with the hydrochloric acid 

 and allowed to cool. Baudouin's Test for Sesame 

 Oil. With 2 volumes of the oil to be tested shake 1 

 volume of a solution consisting of o. I gram of sugar 

 dissolved in 10 c.c. of hydrochloric acid, specific grav- 

 ity 1. 18. In the presence of sesame oil, the oil, upon 

 separation, will be cherry-red. According to Lewin, the 

 reaction is carried out as follows : cover in a test-tube 

 0.5 gm. of finely pulverized sugar with 2 c.c. of the 

 oil, then pour very carefully down the sides of the 

 tube 1 c.c. of hydrochloric acid, sp. gr. 1.18. In the 

 presence of sesame oil a rose-red zone is formed within 

 I to 5 minutes. According to Millian, this test is 

 more delicate when carried out with the well dried 

 free fatty acids, which have been obtained from the oil. 

 Villavecchia and Fabris replace sugar and hydrochloric 

 acid by fulfurol. T., Baumann and Goldmann's, 

 for Cystm. If a solution of cystin be shaken in 

 caustic soda with benzoyl chlorid, a voluminous pre- 

 cipitate of benzoyl cystin will be produced. The 

 sodium salt occurs as silky plates, readily soluble in 

 water, but nearly insoluble in an excess of caustic soda. 

 T., Bechi's, for Cottonseed Oil. Upon heating with 

 an alcoholic-ethereal silver nitrate solution cottonseed 

 oil eventually upon addition of colza oil) yields a red- 

 dish-brown color ; olive oils and other oils remain 

 uncolored. Becker's Reaction for Picrotoxin. The 

 alkaloid reduces Fehling's solution upon the applica- 

 tion of gentle heat. T., Behren's, for Fatty Oils. 

 When treated with a mixture of equal parts of sulfuric 

 acid of sp. gr. 1. 835 to 1. 84, and nitric acid of sp. gr. 

 1.3, different oils show different results. Sesame oil 

 yields a green color. Beissenhirtz's Reaction for 

 Anilin. On the addition of a grain of potassium bi- 

 chromate to a solution of anilin in concentrated sul- 

 furic acid, the solution becomes first red, then blue, 

 the color gradually disappearing. T., Benedict's, 

 for HC1 in the stomach, consists in auscultation 

 over the stomach after the patient has swallowed 

 a small quantity of saturated solution of sodium bicar- 

 bonate. Normal hydrochloric acidity is indicated by a 

 fine crepitation, superacidity by an earlier and louder 

 sound, and in anacidity the crepitation is absent. 

 Benzoic Acid. See Schacht. T., Berthelot's, for 

 Phenol. An ammoniacal solution of phenol treated 

 with sodium hypochlorite produces a beautiful blue 

 coloration. T., Berzelius', for Albumin. All al- 

 buminous substances (except peptone) are precipitated 

 from their aqueous solutions by metaphosphoric acid 

 in freshly prepared concentrated solution. Bieber's 

 Reagent. Equal volumes concentrated sulfuric acid, 

 34 



red nitric acid, and water. T., Biel's, for Cocain. 

 On heating a solution of o. 1 gm. of cocain salt in 1 

 c.c. of concentrated sulfuric acid for several minutes 

 on a water-bath the addition of several c.c. of water 

 causes the formation of a white crystalline precipitate 

 of benzoic acid. T., Biffi's, for Bile. Acidify 150 

 c.c. to 200 c.c. of urine with sulfuric acid; add drop 

 by drop a 5 r / ( barium chlorid solution, using about 30 

 drops to every 100 c.c. of urine. Pour oft' the liquid 

 and collect the soft precipitate on absorbent cotton and 

 spread evenly. Place a crystal of potassium bichro- 

 mate upon the surface of the precipitate, and in the 

 presence of bile a green ring will form around the 

 crystal, changing to blue and then to red. A small 

 amount of albumin will not interfere with the test, but 

 if much is present the use of a saturated solution of 

 sodium sulfate is recommended instead of the sulfuric 

 acid. Bile. See Biffi. B. Acids. See Mylius. 

 B. Pigments. See Barral, Capranica, Dragen- 

 dorff, Dumontpallier, Fleischl, Gluzinske, Grittbert, 

 Jolles, Rasmussen, Riegler, Roman- Delluc, Schiesinyer, 

 Schmidt, Stokz-is. Bischoff 's Reaction for Gallic 

 Acid. A red coloration results upon heating gallic acid 

 with dilute sulfuric acid and cane-sugar. Biuret Re- 

 action for Urea. Melt urea completely in a dry test- 

 tube ; continue the heat for some time. When cold, dis- 

 solve in water, add abundant caustic soda and a dilute 

 solution of copper sulfate drop by drop. The solution 

 becomes first pink, then reddish-violet, and finally 

 bluish-violet, according to the amount of copper 

 sulfate added. Blood. See Antiserum, Bremer, 

 Crystalograp/iic, Kobert, Ladendorff, Selmi, Strure. 

 Boas' Reagent. A solution of tropreolin or paper 

 saturated with such . a solution. Bodde's Reac- 

 tion for the distinction between resorcin and phenol, 

 benzoic acid and salicylic acid. A solution of resorcin 

 yields a violet color with sodium hypochlorite, which 

 fades to yellow ; on the addition of more hypochlorite 

 solution and application of heat a yellowish-red or 

 brown color is produced. If ammonia is added before 

 the addition of the hypochlorite, a violet color first 

 results, which changes to yellow, and on heating 

 passes into dark green. Phenol, salicylic acid, and 

 benzoic acid yield a slight color with hypochlorite only 

 upon heating. Upon previous addition of ammonia 

 the acids are not colored. T., Boernstein's, for 

 Saccharin. Extract the substance to be tested with 

 ether ; remove the ether and heat with resorcin and 

 sulfuric acid and next add an excess of soda solution. 

 In the presence of saccharin a strong fluorescence is 

 produced. According to Hooker, other substances, 

 e.g., succinic acid, also produce this reaction. Bos- 

 ton's Reaction for Bence-Jones' Albumose. It 

 depends upon the presence in the albumose of loosely 

 combined sulfur: (1) 15 to 20 c.c. of filtered urine 

 are placed in a test-tube and to it an equal quantity of 

 saturated solution of sodium chlorid is added, and the 

 whole shaken ; (2) 2 c.c. to 3 c.c. of a 30^ solution 

 of caustic soda are now added and shaken vigorously ; 

 (3) the upper one-fourth of the column of liquid is 

 gradually heated over the flame of a Bunsen burner to 

 the boiling-point, whereupon a solution of lead acetate 

 I io'f ) is added, drop by drop, boiling the up} er previ- 

 ously heated stratum of liquid after each additional 

 drop ; (41 when the drop of lead acetate comes in 

 contact with the liquid a copious pearly or cream- 

 colored cloud appears at the surface, which becomes 

 less dense as the boiling-point is reached ; and when 

 boiling is prolonged for one-half to one minute, the 

 upper stratum shows a slight browning, which deepens 

 to a dull black. This lessens in intensity toward the 

 bottom of the tube. After standing the reaction be- 



