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no evidence that Tween 80 has an emulsifying actionin the small intestine, and it would be premature todraw any firm conclusions from these two observations ;but clearly further trials are justified.

Annotations

INTRINSIC AND EXTRINSIC LIPOID

PNEUMONIA

CHRONIC pulmonary consolidation caused by animal,vegetable, or (most commonly) mineral oils or fatsintroduced into the respiratory tract for diagnostic ortherapeutic purposes has often been reported since itwas first described by Laughlen’ in 1925. The patho-logical process is a foreign-body reaction. Either theoils themselves or the fatty acids formed by hydrolysisof the animal and vegetable ones (mineral oils are nothydrolysed by the tissues), act as irritants and stimulatethe surrounding lung to form fibrous tissue with giant-cells, also causing an accumulation of macrophages. Mostof the early cases resulted from retention of iodisedpoppy-seed oil after bronchography. But similar lesionswere found in debilitated infants who had inhaled milk-mixtures or cod-liver oil ; and routine autopsies at infants’hospitals revealed this " lipoid pneumonia" around

deposits of butter-fat or fish-oils in some 2-7% of thechildren dying of all causes.2 Liquid paraffin taken as alaxative was also implicated ; and by 1943, whenSweeney 3 analysed the 264 published cases of lipoidpneumonia, nearly half were ascribed to liquid paraffintaken internally. French observers later noted that a

frequent cause was nose-drops and throat-sprays con-taining mineral oils. The idea that oils only reach thealveoli in debilitated or unconscious patients had soonto be abandoned-typical lung lesions from inhaled oilshave repeatedly been demonstrated even in healthyadults. Animal experiments had already shown thatmineral oils, particularly when medicated with mentholor other local anaesthetics, can run down the tracheainto the bronchial tree without causing any cough.Liquid paraffin inhibits ciliary action and the normaloutward now of mucus, and once mineral oils reach thealveoli they may remain there indefinitely, since they are notsaponified, unless they are expelled by postural drainageor coughing or carried away by phagocytes. The macro-phages can probably deal effectively with small quantitiesof oil but larger amounts may be aspirated again. Oil canusually be found in the sputum of even the most chroniccase of lipoid pneumonia-either small droplets inside themacrophages or bigger ones lying free, representingperhaps conglomerations of droplets that have escapedfrom disintegrated phagocytes.

According to Volk and his colleagues 4 in Brooklyn,patches of unsuspected lipoid pneumonia, usually pro-ducing no characteristic symptoms or signs, can be foundin many of the chronic sick, especially those who arebedridden, if the lipoid is looked for thoroughly enough.At the Jewish Hospital for Chronic Diseases their routineinvestigations of 389 patients revealed no less than 57cases of lipoid pneumonia-an incidence of nearly 15%.More than half the 57 patients had Parkinson’s disease,disseminated sclerosis, or cerebral palsy, 3 had extra-

pulmonary cancers, and the remainder were arthritics,hypertensives, arteriosclerotics, and so forth. Though16 of them were over seventy, there were 10 under fifty,so this condition is not confined to the aged. All the

patients had their sputum examined for fat and an X-ray1. Laughlen, G. F. Amer. J. Path. 1925, 1, 407.2. Houck, G. H. Practitioners Library of Medicine and Surgery.

New York, 1938 ; suppl. vol. XIII, p. 385.3. Sweeney, W. J., cited by Volk et al. (ref. 4).4. Volk, B. W., Nathanson, L., Losner, S., Slade, W. R., Jacobi, M.

Amer. J. Med. 1951, 10, 316.

film of the chest. When a diagnosis of lipoid pneumoniawas made by these methods it was confirmed by needlingthe lung and searching for lipoid in the exudate. Thestudy extended over some years, so the reliability ofthe investigations could often be tested at autopsy. Ofthe 8 patients with positive findings who died during thestudy 6 were submitted to autopsy and the diagnoseswere fully confirmed. On the other hand, no lipoidpneumonias have been discovered at autopsy among theremainder of the series. This supports the view of Volket al. that the condition can always be diagnosed duringlife. But the investigations must include a search forlipoid in sputum or exudate ; with routine X-ray filmsalone it will sometimes be impossible, for example, todifferentiate between lipoid pneumonia and bronchogeniccarcinoma.

It is when carcinoma is suspected that the diagnosis oflipoid pneumonia becomes most important ; and a furthercomplication has lately been introduced by Navasquezand others 5 at Guy’s Hospital. A woman who had beentreated by radiotherapy for pulmonary carcinoma dieda few months later and was found to have areas of lipoidpneumonia in both lungs corresponding accurately to thedistribution of the irradiation. On section the consoli-dated parts of the lungs were found to contain manyfat-filled macrophages, and the pathological picturewas like that of an inhalation lipoid pneumonia ; but thepatient had not either taken or otherwise used anypreparation of mineral oil,- so far as she knew, andchemical analysis showed that the oily droplets werelargely composed of cholesterol esters, suggesting thatthey were formed by degeneration of the patient’s owntissues. Much the same fatty changes were subsequentlyobserved in 4 consecutive lung carcinomas not treatedby irradiation. Macrophages containing " endogenous "lipoid, recognisable by its rotating polarised light, are

sometimes seen in the alveoli when the lung parenchymahas suffered chronic injury short of necrosis. Boyd 6mentions their occurrence in pulmonary tuberculosis andchronic suppuration, and in the vicinity of large infarcts.Nicholson, in his account of suppurative pneumonia,included a photomicrograph of lung containing lipoidmacrophages but did not discuss their possible significance.Since cholesterol esters are a normal constituent of alltissue cells, it is not surprising that they may be found inthe lung ; and the fatty changes that Navasquez and hiscolleagues have demonstrated in the lung seem to be dueto a liberation of the cholesterol from degenerated tissuecells. The lung, in fact, is behaving just as the heart,liver, and kidneys do in some types of chronic injury.

SEX HORMONES IN DIABETES

THE new light which Prof. B. A. Houssay now castson the problem of diabetes is reminiscent of his importantwork on the diabetogenic influence of the anterior

pituitary. At the Ciba Foundation, London, on July 3,Professor Houssay reviewed his group’s work on theinfluence of sex hormones on the incidence and severityof experimental diabetes in the rat ; - but he first warnedhis audience not to accept these results for other animalsor for man. When 95% of the pancreas has beenremoved, diabetes develops in three stages. In thefirst stage, 1-2 months after the operation, the animalgains weight and shows no hyperglycaemia or glycosuria ;but the impending diabetes is foreshadowed by reducedcarbohydrate tolerance. The second stage, at the3rd or 4th month after operation, is marked by post-prandial glycosuria and increasing appetite as well as byfurther impairment of carbohydrate tolerance. Thenfollows the third stage of manifest diabetes, with a fastingblood-sugar exceeding 150 mg. per 100 ml., glycosuria,5. De Navasquez, S. J., Trounce, J. R., Wayte, A. B. Lancet, 1951,

i, 1206.6. Boyd, W. Textbook of Pathology. London, 1947 ; p. 435.7. Nicholson, H. Lancet, 1950, ii, 549, 605.