Ten patients are presented with tumours complying with the criteria established by the World Health Organization for 'mixed tumours of the lung'.A slowly growing intrabronchial neoplasm indistinguishable from a pleomorphic adenoma (mixed salivary tumour) and a peripheral circumscribed tumour with most of the features of a chondromatous hamartoma were considered benign.Of eight malignant neoplasms two were regarded as 'pulmonary blastomas', one with a benign epithelial tubular component and the other with cytological evidence of malignancy in the tubular epithelium; in both, the stroma was 'embryonic' and pleomorphic. Three tumours were considered carcinosarcomas with a mainly epidermoid epithelial component and a pleomorphic spindle-cell connective tissue component. In the remaining three tumours the malignant epithelial component showed mixed, viz., epidermoid, tubular, and a variety of undifferentiated appearances, while the 'stroma' exhibited features seen in both blastomas and carcinosarcomas. These three neoplasms were considered 'transitional'.The spectrum of appearances encountered constitutes, in our opinion, a serious objection to the thesis that peripheral pulmonary blastomas and carcinosarcomas are distinct entities with a separate histogenesis. Exceptions were found to 'blastomas' being peripheral and carcinosarcomas being central growths. A case is made for reclassification of the benign and malignant neoplasms included in the WHO group IX 'mixed tumours of the lung'.

PLATES XLI-XLIV)THE peculiar vascular formations seen in glioblastomas and some other cerebral tumours present an interesting problem in pathogenesis. These complex, sometimes almost angioma-like, systems of coiled blood sinuses, found chiefly at the growing margins of the tumours and referred to by such terms as glomerular structures (Tooth, 1912-13 ; Deery, 1932 Deery, , 1933, angioplastic processes (Scherer, 1934-35), endotlielial proliferations, adventitial hyperplasia, etc., give an impression of remarkable proliferative activity on the part of the vascular tissues. One form in particular, referred to by Penfield ( 1 9 3 1~ and b ) and Elvidge et al. (1937) as inward proliferation and by Gough (1940) as intravascular formations ( fig. l), shows an apparent sprouting of the lining endothelium of the blood vessels with the formation of processes bridging the lumina and dividing them into several coiled channels ( fig. 2). J. PATH. BACT.-VOL. LXVIII (1064) 231 1934-35. Arch. path. Anat., ccxciv, 823. 1912-13. Brain, xxxv, 61. ii, 157. Assoc. for Research in Nervous andMental Diseases, xvi, 107. 745.

The history and the clinical and necropsy findings are presented of a patient who died from Aspergillus fumigatus pyaemia occurring as an opportunistic infection complicating a dissecting aortic aneurysm. The diagnosis was made (and treatment instituted) during life: it rested upon repeated isolation of the organism from tracheal aspirations, a positive blood culture and positive serum precipitin reactions to A. fumigatus. Debilitating disease along with large doses of antibiotics and corticosteroids provided the conditions necessary for the normally saphrophytic fungi to become pathogenic. As the therapy for aspergillosis is still ineffective, the danger of prescribing large doses of antibiotics together with corticosteroids is stressed.Interest in the fungal diseases and especially those caused by the aspergillus species has greatly increased over the past decade. As a result, attempts to culture aspergilli are being made more frequently and the advent of skin and precipitin tests has enabled the distinction to be made between contamination and infection. Even so it is extremely rare for the diagnosis of disseminated aspergillosis to be made during life (Caplan, Frisch, Houghton, Climo, and Natsios, 1968;Rifkind, Marchioro, Schneck, and Hill, 1967); the diagnosis is usually made by histological and cultural examination of necropsy specimens. We present a case of disseminated aspergillosis diagnosed during life and treated accordingly. The gross debility of the patient and the therapeutic barrage to which he was subjected provided the conditions for a disseminated fungal infection. CASE REPORTA 51-year-old man employed as a store-keeper in a car factory was admitted to hospital because of severe throbbing pain between the scapulae and also in the lumbar region. Thirteen years earlier the upper and middle lobes of the right lung were resected for caseating tuberculosis. For two years before admission he had been treated for severe fluctuating systemic hypertension.On examination he was in severe pain and there was some tenderness and guarding in the right hypochondrium. All the pulses were present and strong; the blood pressure was 240/100 mm. Hg. Later, on the day of admission, he developed a grey facies and profuse sweating. A leaking abdominal aortic aneurysm was diagnosed and a laparotomy was performed on the following day. At laparotomy the findings were those of a slight aneurysmal dilatation of the aorta just above the aortic bifurcation with some oedema of the adventitia. Free blood was not present in the abdomen. No surgical procedure was undertaken and the abdomen was closed. On the fourth post-operative day he complained of lumbar pain and was noted to be slightly jaundiced; serum bilirubin was 69 mg./100 ml. and the haemoglobin 13-9 g./100 ml. The blood pressure was 260/160 mm. Hg, and the temperature varied between 35 5' C. and 37 5' C. A septicaemia was suspected and after three blood cultures had been taken cephaloridine was given intravenously (blood cultures proved negative). On the sixth post-o...