The case is described of an eight-year-old Nigerian boy who died from olfactory neuroblastoma which presented with nasal obstruction and epistaxis. Autopsy showed intracranial extension of the tumour into the frontal lobe, and histology revealed undifferentiated neuroblasts, forming rosette in some areas and producing tangled neurofibrils in others. The histogenesis of the tumour and its diagnosis are briefly discussed.

Haemangiopericytoma is only rarely localized in the nasal cavity. The authors' experience with one case has prompted them to review the literature critically, in order to understand better the most appropriate diagnostic procedures and therapeutic measures.

A case of intraductal carcinoma of the minor salivary gland is reported. It appears to represent the preinvasive phase of infiltrating salivary duct carcinoma. A five-year follow-up showed neither recurrence nor metastasis.

A case of tuberculous granuloma of the epiglottis is presented. The presenting symptoms were hoarseness and painful dysphagia, and the laryngoscopic appearances resembled carcinoma. Histological examination of the biopsy material was diagnostic, emphasising the difficulty of diagnosis in the general population.

Hearing changes in patients treated with gentamicin have been prospectively investigated. A group of patients who had a similar spectrum of clinical conditions but did not receive gentamicin have been studied as a control group. The audiometric technique was first validated by recording audiograms from health volunteers, once in an anechoic chamber and twice in a ward. It was concluded that changes in threshold <20 db. should not be regarded as significant when measured in a ward.

In the gentamicin-treated group an initial audiogram was not a reliable measure of the patient's normal hearing because of the influence of their clinical condition. Twenty-one of the control patients were elective admissions to hospital and had their hearing first tested when they were clinically well. There was a 24 per cent incidence of unexplained hearing abnormalities—similar to the incidence of hearing loss in the gentamicin-treated group at follow-up. It was concluded that aminoglycoside auditory toxicity should not be assessed retrospectively.

The incidence of hearing changes in the control and gentamicin-treated groups were similar. Possible causes of hearing loss in surgical patients are discussed and recommendations are made for the conduct of future studies of drug-induced auditory toxicity.