1166 FOODS AND FOOD ADULTERANTS. 



and absorbed during digestion was proved by the detection of tin in different organs 

 of a dog and a rabbit fed with food containing tin. Subsequently in two cases uri- 

 nary analysis showed that with men also a part of the tin introduced into the stom- 

 ach by such foods was absorbed. Experiments were made to settle the question how 

 far the introduction of tin into the circulation could work injury. Those which 

 were made on three species of animals frogs, rabbits, and dogs with subcutaneous 

 injections of sodium-stannous tartrate showed that the introduction of auoucaustic 

 tin salt into the animal organism, even though it be not introduced directly into the 

 circulation, caused pathological symptoms and finally death. 



The conclusion was drawn that even minimal doses of tin, when freqently repeated, 

 destroy health and finally cause death. 



With regard to the possibility of chronic tin poisoning it was established that 

 small doses of tintriethyl acetate subcutaueously injected, when frequently given, 

 caused an intoxication culminating in death, thus corroborating the results of 

 White. 1 It is found that the toxic action of tintriethyl acetate is much greater than 

 that of sodium-stannous tartrate, and it appears that the poisonous action of this 

 compound is not due to the metal alone. Tintriethyl acetate, sodium-stannous tur- 

 trate, and stannous chlorid (in milk) were also introduced through the mouth. 

 These experiments showed the poisonous qualities of tin combinations. The authors 

 believe they are able to answer in the affirmative the question whether food con- 

 taining tin can cause a general intoxication or a chronic tin poisoning, aside from an 

 accidental local action. 



TECHNICAL DETERMINATION OF /INC.' 2 



Prepare a solution of zinc ferrocyanid by dissolving 44 grams of the pure salt in 

 water and diluting to a liter. Standardize as follows: 



Dissolve exactly 300 ing of pure zinc oxid in a beaker in 10 cc of strong hydro- 

 chloric acid. Now add 7 grams of ammonium chlorid and about 100 cc. of boiling 

 water. Titrate the clear liquid with the ferrocyanid solution until a drop, when 

 tested on a porcelain plate with a strong aqueous solution of uranium acetate, 

 shows a brown tinge. About 16 cc of ferrocyanid will be required, and according- 

 ly nearly this amount may he run in rapidly before making a test, and then the 

 titration finished carefully by testing after each additional drop of ferrocyanid. 

 As soon as a brown tinge is obtained, note the reading of the burette, and then 

 wait a minute or two and observe if one or more of the previous tests do not also 

 develop a brown tinge. Usually the end point will be found to have been passed by 

 a test or two, and the proper correction must then be applied to the burette read- 

 ing. Finally make a further deduction from the burette reading of the amount of 

 ferrocyanid required to produce a brown tinge under the same conditions when no 

 zinc is present. This correction is about two drops or 0.14 cc. 



Two hundred mg of zinc oxid contain 160.4 mg of zinc and one cc of the above 

 standard solution will equal about 0.01 gram of zinc or about 1 per cent where one 

 gram of ore is taken for assay. 



Prepare the following for the assay of ores: 



(1) A saturated solution of potassium chlorate in nitric acid, made by shaking an 

 excess of the crystals with the strong, pure acid in a flask. Keep the solution in an 

 open flask. 



(2) A dilute solution of ammonium chlorid containing about 10 grains to the liter. 

 For use heat to boiling in a wash bottle. 



(3) A wash bottle of hot water : 



Take exactly one gram of ore and treat in a 3.5 inch casserole with LT> << o! tho 

 chlorate solution. Do not cover the casserole at first, but warm gently until any 



1 Arch.exp. Pathol. u. Pharm., 18, 53. 



1 Von Schulz and Low. .1. Analytical and applied ('hem.. I*!'!', ti. l!'l. 



