374. HALOIDS OR HALOGENS 



to stand for 6 to 12 hours. At the same time, dissolve the sodium 

 carbonate and bicarbonate in 5 more liters of water. Pour the solu- 

 tion of the sodium salts in the mixture of chlorinated lime, agitate 

 thoroughly, then allow to remain undisturbed so that the calcium 

 carbonate will settle. At the end of one-half hour, siphon off the 

 liquid and filter through double paper. The filtrate is the Carrel- 

 Dakin solution. Protect from the light. 



Since the solution does not keep well, it is wise to verify the 

 strength from time to time as follows: To 10 mils of the solution 

 add 20 mils of a 1 — 10 solution of potassium iodide and 2 mils of 

 acetic or hydrochloric acid. Titrate this mixture dropwise with a 

 deci-normal solution of sodium thiosulphate until decoloration is 

 complete. The amount of thiosulphate solution in mils multiplied by 

 0.03725 will give the weight of sodium hypochlorite in 100 mils of 

 the solution, 12 to 13 mils should be required for the reaction. Thus 

 13 multiplied by 0.03725 equals 0.485 gms. (0.48 per cent.). 



The alkalinity may be tested from time to time by dropping a 

 few centigrams of phenolphthalein in powder form upon 20 mils of 

 the solution. There should be no change in tint. 



lODUM — IODINE 



Iodine is a nonmetallic element obtained from the ashes of sea 

 weed and is found in the mother liquor obtained in the purification 

 of Chile saltpeter. It occurs as bluish-black friable crystals, hav- 

 ing a metallic lustre, peculiar odor and sharp acrid taste. Upon 

 heating it gives off a violet colored vapor. One gram is soluble in 

 2950 inils of water, 12.5 mils of alcohol, 80 mils of glycerin, and 

 very soluble in ether, chloroform and sohitions of potassium iodide. 



Preparations and Doses. 



loduin. H. and C. 3 ss — j ; 2. — 4. Dog. ISTot often used. 

 Tinctura lodi. Iodine 7 grams, potassium iodide 5 grams, 

 water 5 mils, and alcohol enoiigh to make 100 mils. 



Liquor lodi Compositus (Lugol's Solution). 5 per cent, of io- 

 dine in 10 per cent, aqueous solution of Potassium Iodide. 



H. and C. o ij — iv; 8. — 15. Dog, HI ij— x; 0.12—0.6. 



* Tinctura lodi Decolorata N. F. This is really a solution 



of iodides and does not contain free iodine. 

 Unguentum lodi. Iodine 4 gms., Potassium Iodide 4 gms., 



glycerin 12 gms., and benzoinated lard 80 gms. 



Incompatibles. Iodine is incompatible with alkaloids, mineral 

 salts, ammonia, carbonates, starch and mucilage of acacia. It acts 

 strongly upon turpentine and some other volatile oils. The tincture 



* Unofficial. 



