SEVERAL observers have shown (Pfeiffer, Emmel and Gardner, 1940; Korenchevsky and Ross, 1940) that apart from the occasional production of urinary calculi and glomerulo-nephritis, prolonged oestrogen administration has only a slight effect on the kidneys of rodents, and never induces neoplasia. Matthews, Kirkman and Bacon (1947) were the first to demonstrate that the kidneys of the male golden hamster (Cricetus auratus) are the exception as they possess a peculiar susceptibility to renal neoplasia following treatment with oestrogen.The object of this communication is primarily to describe the histogenesis of these oestrogen-induced renal tumours in the male hamster, and to discuss other related problems which might help towards a better understanding of oestrogenic neoplasia. MATERIAL AND METHODS.Forty male golden hamsters, all approximately 12 weeks of age, each received a 20 mg. pellet of pure diethylstilboestrol subcutaneously in their right flank. An equal number of untreated male hamsters of the same group were kept as controls.For routine histological study the kidneys were fixed in alcoholic Bouin, and subsequently stained either in haematoxylin and eosin or by a modification of Masson's light green. In order to test for the presence of intracellular lipids, both fresh and formalin-fixed kidneys were stained with alkaline Sudan IV, Sudan black B and Nile blue sulphate. The pituitaries were fixed in Zenkerformol and differentially stained by Mallory's triple stain. Verhoeff's method was used for the staining of elastic fibres and the Gordon and Sweet procedulre for the presence of reticulin.OBSERVATIONS. Macroscopic description of renal turnours.Six and a half months after stilboestrol treatment had commenced all hamnsters were palpated weekly for the presence of kidney lesions.Although no renal tumours were palpable at this early period of treatment 8 hamsters were killed in order to study the development of early tumour formation. Each of these hamsters possessed very small cortical lesions which varied between 2 and 5 mm. in diameter. Small palpable tumours arose in some hamsters at the end of the 9th month of treatment, and by the beginning of the 11th month every treated hamster had large renal tumours. At the end of the 12th month

[WITH SPECIAL PLATE] Q fever, first described by Derrick (1937) HistologyLung.-Sections from the red and grey areas of the diffusely consolidated right lower lobe showed differences due to stages .in the pneumonic process. In the red area, consolidation was not uniform, the exudate within alveoli having a patchy distribution. Throughout there was intense congestion of blood -vessels. Alveoli were filled with an eosinophil non-fibrillary coagulum in which were a few cells. These consisted of neutrophilic polymorphs and round cells in about equal numbers; red corpuscles were scanty, and were present at only a very few points. The round cells were of different types. A few were lymphocytes and plasma cells, but most were larger mononuclear macrophages which, owing to degenerative changes, -varied in appearance from elements of about plasma-cell size with well-stained cytoplasm and dark nuclei to large pale cells with finely granular or vacuolated cytoplasm and vesicular, often peripheral, nuclei; The vacuolated appearance was striking, and was-not due to the presence of lipoid: the contents of the vacuoles failed to stain with Sudan 111 and were not doubly refractile. The exudate within bronchioles was similar to that in the alveoli, though in and about some respiratory bronchioles there was a higher concentration of neutrophilic polymorphs. There was some oedema of interlobular connective tissues and of the walls of blood vessels within them.In the basal zone of grey hepatization the pneumonic process was more uniform. Here there was little congestion. The alveolar walls were considerably thickened (Plate, Fig. 1), through infiltration by many macrophages and smaller numbers of lymphocytes, plasma cells, and neutrophils. In some there was also early fibroblastic proliferation. Scattered areas showed necrosis and breakdown of septa. Within the alveoli the exudate was cellular (Fig. 2) Brain.-In the foci of cerebral and pontine softening the tissues showed both perivascular and more widespread loosening of texture with occasional small'perivascular haemorrhages (Fig. 4). Some of the capillary vessels showed swelling of their endothelium and a few contained thrombi. No perivascular cellular exudate was present in the affected areas, but there was slight marginal increase of neuroglial cells, and these, with Giemsa staining, contained many cytoplasmic granules. Some of the granules were coarse and irregular in shape and were probably degenerative products, the result of clasmatodendrosis, but others were morphologically, and in their grouping, rickettsiae. Support for their identification as rickettsiae was provided by the' presence of similar bodies in the cytoplasm of some capillary endothelial cells as well as extracellularly in the damaged areas. The same problem has arisen in typhus, and the criteria applied by Wolbach et al. (1922), similar to those given here, appear to be valid. The nervous lesions were probably at a very early stage of development.Spleen.-The Malpighian bodies were very small, and the pulp ...

THERE is an astonishing neglect in the literature of the benign cutaneous condition described by MacCormac and Scarff in 1936, and named by them molluscum sebaceum. An alternative name, kerato-acanthoma, has since been applied, and this has the merit of preventing confusion with molluscum contagiosum, an unrelated condition. It has been the subject of only 4 papers, all by British authors, MacCormac and Scarff (1936), Musso and Gordon (1950), Rook and Whimster (1950) and Beare (1953), and does not yet appear to have reached text-books of dermatology or pathology. That this in no way reflects the incidence of molluscum sebaceum is certain. Indeed, it is not an uncommon condition, and is still very frequently misdiagnosed as squamous-cell carcinoma by both dermatologist and pathologist.Smith, in 1934, described the occurrence in a young man of multiple primary squamous-cell carcinomas of the skin which healed spontaneously and he was unable to find any comparable case in the literature. Since that time there have been eight papers on the subject (Table II) with descriptions of similar lesions in 11 patients. Comparison of the clinical and pathological descriptions of these cases with the natural history and the structure of molluscum sebaceum at once suggests the probability that all the recorded cases of spontaneously healing epithelioma of the skin are in fact instances of molluscum sebaceum.The following account is based on a series of 7 cases of molluscum sebaceum which after biopsy diagnosis were untreated and allowed to run their natural course to spontaneous regression. Numerous other cases have been studied, but are not included here because they were treated by radiotherapy or surgery.Molluscum sebaceum.Clinical features.-Some of the clinical features of the lesions in our 7 cases are summarized in Table I.Histology.-The histological structure of molluscum sebaceum was admirably described and illustrated by Dunn and Smith (1934), though, unfortunately, under the diagnosis of " Self-healing primary squamous carcinoma of the skin." That they were not fully convinced of the correctness of the diagnosis is suggested by their statement that " It may be we are dealing with something which is not quite cancer in the ordinary accepted sense, but which cannot in its early stages be * Medical Research Council Scholar.

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