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THE JOURNAL OF PHARMACOLOGY. 



containing nitric acid, a rose-red to deep 

 red coloration appears. This reaction 

 takes place even in dilutions of 1:100,000. 



Reichert = rieissPs number indicates 

 the number of ccs. of deci-normal sodium 

 or potassium hydroxide solution neces- 

 sary to neutralize the volatile fatty acids 

 obtained trom 5 g. of a fat, when operat- 

 ing according to a definite special method. 

 The Reicherfs numbers formerly in vogue 

 gave the figures for 2.5 g. of fat and 

 are, therefore, only half as large as the 

 Reichert-Meissl 's numbers. 



Reichl's test for glycerin. Equal parts 

 of glycerin, phenol and sulphuric acid 

 are mixed and heated to 120 . After 

 colling, water is poured upon the brown- 

 ish-yellow solid mass and ammonia added 

 drop by drop, whereby the mass is dis- 

 solved to torm a beautiful carmine-red 

 solution. 



Reichl=Mikosch's reagent for albumens 

 consists of benzaldehyde and sulphuric 

 acid containing ferric sulphate. 



Reinsch's arsenic test. A solution of 

 arsenous or arsenic acid in hydrochloric 

 acid is reduced by metallic copper. A 

 gray coating of copper arsenide is formed 

 upon the metal. Antimony and mercury 

 behave similarly ; their absence must, 

 therefore, be proved before the presence 

 of arsenic can be decided upon. This 

 test is also known as Hager's empirical 

 arsenic test (kramato method). 



Remak's solution for hardening mi- 

 croscopical preparations is a mixture of 

 50 ccs. aqueous copper sulphate solution 

 (20 p. c), 50 ccs. alcohol (25 ), and 35 

 drops purified wood vinegar. 



Renard's test for peanut- oil depends 

 upon the isolation ot arachic acid (melt- 

 ing point 74-75 ) by means of the lead 

 salt, which can be separated from lead 



oleate by extraction with ether. For 

 particulars see Chem. Ztg., 1895, p. 451. 



Reuter's test for ^-amidophenetol in 

 phenacetin. The phenacetin is melted 

 with pure chloral hydrate ; if a violet 

 color appears, amidophenetol was present. 

 (Even the purest commercial specimens 

 show a slight rose tint.) 



Reynold's test for acetone in the urine. 

 The distillate from the urine is shaken 

 with freshly precipitated mercuric oxide 

 (from mercuric chloride and potassium 

 hydroxide). If acetone was present, the 

 filtrate will contain acetone-mercury in 

 solution and will respond to the tests for 

 mercury. 



Rheoch's test for free mineral acids. 

 See Molly's test. 



Richardson's reaction for a-naphthol. 

 0.04 g. of naphthol and 0.5 ccs. of nor- 

 mal sodium hydroxide solution are dis- 

 solved in 1 — 2 ccs. of water. Hereto is 

 added a mixture of 0.05 g. sulphanilic 

 acid dissolved in 5 ccs. normal sodium 

 hydroxide solution, and 0.02 g. sodium 

 nitrite dissolved in 5 ccs. normal sul- 

 pluric acid. a-naphthol under these 

 conditions yields a dark blood-red color, 

 which changes to brown upon the addi- 

 tion of dilute sulphuric acid ; ^-napthol 

 causes only a reddish-yellow color. 



Determination of Santonin. — Pharm. 



Zeitung, xlii., 604. 



A weighed quantity of santonin 

 powder is first abstracted with ether, the 

 ether is then distilled off and the residue 

 is boiled with milk of lime and filtered. 

 Aluminium acetate is added to the solu- 

 tion which is then boiled and neutral- 

 ized with magnesium, evaporated to 

 complete dryness and dried after powder- 

 ing at 105 C. for a couple of hours. The 

 powder obtained is then extracted with 

 ether, this evaporated and the residue 

 weighed as santonin. 



