Operation, and This Can Most Easily Be Done If the Solution STITUTE

DR. W. MACKIE : CALCIUM IODATE AS AN IODOFORM SUBSTITUTE. 1867 from 101° to 102° F- It will cool down to blood heat while abundance. Chemical equation shows that calcium iodate in passing through the transfusion apparatus. Care should be contact with hydrochloric acid liberates as nearly as may be taken to see that the temperature is maintained during the four-sevenths of its weight of chlorine. On this fact theoreti- operation, and this can most easily be done if the solution cally depends its use as a gastro-intestinal antiseptic. As be prepared in small quantities at a time. It should in all regards antiseptic action something no doubt depends on the cases be filtered through muslin before use. If it be neces- chemical instability of iodates generally and of this iodate in sary to repeat the transfusion another vein must be opened. particular, on the nascent action of the liberated products, When the patient has been revived and the immediate and in this case on the fact that the base forms insoluble danger of death from syncope is staved oil the extreme rest- compounds such as carbonate and phosphate in contact with lessness and headache that so frequently follow may be alkaline discharges, thus probably facilitating the free treated by large doses of opium or morphia. Any further operation of the acid radicle of the salt, on which of course tendency to syncope is best treated by raising the foot of its particular virtue really depends. the bed and the administration of liquid food and stimulants From this view of its action it is to be inferred that in small quantities at frequent intervals. The great risk of calcium iodate acts more as a destroyer of the products subsequent sepsis must not be forgotten and the convale- of bacterial life than as a bactericide of any very decided scence of such patients is of necessity a slow process. degree of potency. Of its inhibitory power on bacterial Wimpole street, W. growth there cannot however, I think, be any doubt. It would thus closely conform to iodoform in its action. Further, the function of the salt as a dEOdorant, of which I have time and again had ample proof, CALCIUM IODATE AS AN IODOFORM SUB- can be easily understood as the result of its chemical STITUTE AND GASTRO-INTESTINAL action. Iodates decompose sulphuretted hydrogen, precipi- ANTISEPTIC. tating it in part as sulphur, in part oxidising it into sulphuric acid. As the fcetor of foul discharges is no doubt BY WILLIAM MACKIE, M.A., M.D. ABERD., in many cases due to volatile sulphur compounds, if not VISITING PHYSICIAN AND SURGEON, DR. GRAY’S HOSPITAL, ELGIN. actually to sulphuretted hydrogen itself, we naturally expect a similar action in their case. To pass to the practical side, the substance itself is most MANY Sonstadt came to the conclusion that the years ago easily prepared-in fact, it can be prepared by any dispensing minute quantity of iodine contained in sea-water is present in chemist as follows : Prepare an aqueous solution of iodine4 the form of calcium iodate.1 To this substance, existing, as in potassium iodide. Dilute the same till it just transmits z a of three inches. Stir some he calculated, in the proportion of one part in about 250,000 light through depth up bleaching ’’ with water and filter into iodine with parts of sea-water, he attributed not only the salubrity of powder solution, occasional stirring. After a time a crystalline precipitate the sea, the medium of the of the but, through atmosphere, makes its appearance. If it is not white, but land also." At a somewhat later date the same chemist made perfectly some shade of brown or slate-grey, add more iodide of "experiments on the properties of iodate of calcium as an to 3 potassium and stir. Run in the bleaching solution complete antiseptic and disinfecting agent." Some of these experi- decolourisation of the iodine solution. Before the ments I have with this difference-that where collecting repeated, precipitate add a small quantity of very dilute hydrochloric Sonstadt used the I have used a saturated mostly dry powder acid to dissolve any carbonate of lime that may have formed solution of the but the results obtained me have in salt, by the Collect on wash once or twice instance been in accord with those obtained during process. filter, every complete with cold and on or in an oven at him. water, dry blotting paper by a temperature not much exceeding 100° C. The is About 15 months I to use calcium product ago began tentatively + 6 The particular to be attended to is to iodate in as an in Ca(Ioa)2 H2O. point surgical practice antiseptic dressing place the iodide of in excess the of iodoform. For about the same time I have been keep potassium during precipita- using it, tion. Part of the iodide is itself oxidised to an iodate and though to a less extent, in medical practice also. The results by double with the chloride of calcium in both cases have led me to conclude that calcium iodate is decomposition present in the bleaching solution falls as iodate of calcium. By this a substance to of considerable value both likely prove very particular action on an iodide in alkaline solution the for external and internal use. Up to the present, however, quantity of iodide of is reduced and observations have been more directed to its potassium gradually my particularly may thus in time become insufficient to keep all the iodine in surgical applications. For the last six months or more I have solution. From this reaction the of calcium used it without hesitation in all kinds of work where secondary yield surgical iodate is always in excess of what might be expected from iodoform is usually indicated and, I may say, to the almostthe oxidation of the quantity of iodine taken. total exclusion of the latter substance, and belief in its simple my Iodate of calcium is without taste or smell, though a slight has increased with its continued use. efficacy only iodine odour may be detected on opening a bottle in which it The of the action of calcium iodate as an anti- theory has been kept for some time. At 115° C. I found its is not far to seek. It is an iodine contain- septic compound to be about one in 380 of water. In solutions cent. of iodine and in addition 16 cent. of solubility parts ing 51 per per of even this it shows a wonderful with dilution, however, degree available oxygen. On contact putrescible organic matter, of potency in inhibiting decomposition, in preserving food whether in acid or in alkaline medium, like other iodates substances, and in checking foetor, as the following examples it liberates iodine. In alkaline solution, while the slowly will show (Examples 1 and 3 are practically repetitions of organic matter is being oxidised by the oxygen set free from experiments by Sonstadt). the decomposing iodate, the iodine by a reaction well known . 1. On March 21st, 1899, about two drachms of freshly passed to occur in alkaline media re-forms iodate slowly through urine were placed in an unsterilised test-tube and an equal the of water. The iodate so re-formed in decomposition of a saturated solution of calcium iodate added to contact with another of matter quantity portion putrescible yields it. The mixture would thus contain about one part of iodate further of free and iodine to act as proportions oxygen in 800 of the solution. A control was made in a similar and so on. The so to parts before, process, therefore, is, speak, test-tube to the of urine its own a continuous one. As most are alka- by adding same’quantity pathologipal discharges bulk of distilled water. Both tubes were freely to line we have in such cases the conditions exposed present necessary the air. At the end of a week the control stank of the continuous action of an iodate. In an acid abominably, medium, while the tube the iodate was fresh and in the of substances such as containing perfectly also, presence reducing easily exhaled a somewhat aromatic odour which could not in oxidisable iodine is liberated and the any organic matter, by be associated with urine. It continued to exhale the of water it sets free which is used way decomposition oxygen up same pleasant odour and appeared perfectly sweet and clear in any unstable that be oxidising organic compound may up to June 26th when the was to an The iodine in this case into acid experiment brought present. passes hydriodic end by an accident to the tube. A similar by or an iodide and so ceases to act. experiment eventually If, however, Sonstadt, where, however, the salt had been added to the acid in a medium be for dry present hydrochloric-as, the urine, would indicate the of its in the not the possibility potency example, gastric juice-chlorine, though only extending over a much longer interval. Another experiment substance liberatefi, is ct::r-atoly rhe one liberated in greatest 1 Chemical News, 1872, vol. xxv., p. 197. 4 The iodine is not necessary. A solution of potassium iodide 2 Ibid., p. 242. may be used alone, the iodine being set free by the bleaching solution 3 Ibid., vol. xxviii., p. 297. and dissolving in the excess of iodide. 1868 DR. W. MACKIE: CALCIUM IODATE AS AN IODOFORM SUBSTITUTE. went to show that even in the proportion of about 1 in 7000 heal ’by granulation, I have found the dry powder an excel- parts the decomposition of urine was markedly delayed by lent dressing.

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