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1195 THE ACTION OF LIPIODOL.-MEDICAL AMERICANA. be used prophylactically to keep marmosets in health and fine breeding condition. These little creatures are highly susceptible to rickets, and though there are a few scattered records of young being born in this country, they do not seem ever to have survived. Under the influence of the mercury-vapour quartz lamp, however, young have been born at the Lister Institute and have thriven. The possibility of breeding monkeys in captivity offers new opportunities to workers in psychological laboratories, doing the type of work, for instance, which has been done by Prof. R. M. Yerkes at Yale. A knowledge of the means to keep them in health is of importance to all laboratory workers who use monkeys, as well as to those who are in charge of menageries and to those who keep monkeys as pets. THE ACTION OF LIPIODOL. IODISED oil, in one form or another, has now become a valuable instrument in the technique of radiological examination of the lung. Whilst firmly convinced of its great value as a diagnostic procedure, Dr. E. Archibald (Montreal) and Dr. A. Lincoln Brown (San Francisco) have recently published a careful review of the subject, in which they call atten- tion to the possible dangers of its use when intro- duced into the tracheo-bronchial system. They have concentrated their attention chiefly on the particular preparation sold under the registered name lipiodol, which is an iodised vegetable oil containing 40 per cent. of iodine. After injection into the tracheo- bronchial system a large percentage of the oil is eliminated by expectoration or swallowing ; this the authors consider of no interest. A proportion of the oil is, however, absorbed, and in certain cases has been found to cause symptoms of iodism. Most of these cases appear to have shown only mild symptoms of iodism, but a few more serious complications have arisen. In experiments on cats the authors found the oil present in a minute state of subdivision in many of the tissue elements that make up the pul- monary structure-even in the cartilage of the smaller bronchi. These facts were demonstrated by the use of Scharlach R. in sections. The authors believe that this absorption-which may be in some way asso- ciated with an internal digestive power possessed by the lung-is likely to be delayed in an extensively diseased lung, especially if cavities are present, and may even so fill alveoli as to interfere with oxygen absorption. Much apparently depends on the iodine tolerance of the patient, which, fortunately, in most individuals is high. The authors state, on the autho- rity of Forestier, that after an intratracheal injection of 20 c.cm. of lipiodol, the daily elimination of the iodine during the first two weeks is 0 -02 g. They have noted cases in which the lipiodol shadow showed in the radiogram for 15 months, though in the majority of cases the shadows only persist for a few weeks. With regard to the technique of administration, the risks of local sepsis, a false passage and laryngeal oedema are discussed, and the suggestion is made that for the first injection, at least, the bronchoscopic method should be used, in order to obtain a satis- factory and direct visual examination of the injected field. The effect of the cough reflex in disseminating the oil into distant parts of the lung is also emphasised. Cough reflexes have not been noted in ramifications of bronchi smaller than those of the second order. It has been stated that, inasmuch as the normal tracheo-bronchial tree can hold 5000 c.cm. of air, 40 c.cm. of injected lipiodol can be regarded as a small amount, but it must be remembered that in disease this tracheo-bronchial capacity may be diminished by as much as 50 per cent. Moreover, since lipiodol is known to float on the top of sputum, the blocking of a small bronchus may occur, especially at points where the cough reflex is not excited. As to the therapeutic effect of lipiodol on the tuberculous process the authors are in doubt, but consider that in certain cases and in properly regu- 1 Jour. Amer. Med. Assoc., 1927, lxxxviii., 1310. lated doses lipiodol may have a similar effect to that of tuberculin. Recent work on this subject by F. G. Chandler and S. R. Gloyne 2 would seem to show that the actual bactericidal effect of lipiodol on B. tuberculosis in vitro is not very great, and that there is no lipolytic action when this substance is injected into the pleural sac of normal rabbits, and no toxic effects on distant tissues. These workers suggest, in fact, that from a purely therapeutic point of view the effect of lipiodol is probably mechanical. In summarising the dangers which may result from the injection of lipiodol, Archibald and Brown record a small number of unfavourable cases which they have collected from the literature, including one case where subacute sepsis was considered to be due to lipiodol injection five days previously. Without any desire to minimise the undoubted value of lipiodol as a diagnostic aid in pulmonary disease, these authors believe that there are definite potential risks which should be weighed before patients are subjected to its indiscriminate use. Probably in the hands of skilled operators these risks are not great, but the method is obviously one which cannot be carried out without proper safeguards and training in acquir- ing the technique. In a later communication 3 the same authors give the results of an experimental investigation with lipiodol. They injected cats intratracheally, and found that cough alone increased the rapidity and degree of penetration of lipiodol and lipiodol-sputum emulsion, and that this action was still more definitely marked with tracheal com- pression. In fact, an actual in-driving effect on the lipiodol was caused by cough. No similar in- driving effect was observed with thick, tenacious sputum. Apparently, whereas coughs may tend to drive a fluid substance, such as lipiodol or lipiodol- sputum emulsion, further down the bronchial tree, it has not the same effect in breaking up and forcing thick, tenacious sputum into the finer ramifications. MEDICAL AMERICANA. AN Exhibition of Early and Later Medical Americana was held in the library of the New York Academy of Medicine, when the new building of that institution was opened last month. The Catalogue contains 95 items, all of which are of interest to students of the history of disease whether they be Americans or no. The first medical publication in the United States, of which a photostatic reproduction is shown, was a broadside printed at Boston in 1677, entitled " A Brief Rule to Guide the Common-People of New England how to order themselves and theirs in the Small Pocks, or Measles." The author was Thomas Thacher, pastor of the Old South Church, in Boston, who had picked up a smattering of medicine sufficient in his day for the needs of his flock. He gives sensible directions for the treatment of the sick, but is, of course, ignorant of inoculation. It was not till 1721 that Benjamin Colman, also a preacher, published at Boston " Some Observations on the New Method of receiving the Small-Pox by Ingrafting or Inoculating," a method of which he was the advocate. Lady Mary Wortley Montagu had only recently described inocula- tion as practised in Constantinople. In 1721, probably after Colman’s publication had appeared, Increase Mather, at one time President of Harvard, republished " Some further Account from London of the Small- Pox Inoculated." The title of the second edition of his pamphlet, reproduced in the Catalogue, refers to a " late Scandalous Pamphlet entituled Inoculation of the Small Pox as practis’d in Boston, &c.," and we are left in doubt as to what attitude the father took towards the innovation of his son, Cotton Mather, who had brought the knowledge of the treatment to New England, where it had been at once acted upon by Zabdiel Boylston. On June 26th, 1721, Boylston inoculated his six-year-old boy, and thus began a controversy which raged for many years in America, 2 Tubercle, 1927, viii., 563. 3 Amer. Rev. of Tub., 1927, xvi., 111.
