Some signs indicating a terminal hypoxic episode have been found in cases of the sudden infant death syndrome (SIDS). These include intrathoracic petechial haemorrhages in the lungs, heart, and thymus. Nevertheless the actual cause of such a hypoxic episode is still speculative. One of the current theories concerning the aetiology of the SIDS is that of Steinschneider (1974). He has suggested that in many cases of sudden infant death there are episodes of prolonged sleep apnoea and while such episodes may be a normal physiological phenomenon, gradually becoming less frequent and completely disappearing within the first year of life, it is possible that such an episode of apnoea may become so prolonged as to cause the death of the child by hypoxia.Naeye, in 1973, looked for evidence of chronic hypoxia in the lungs of cases of SIDS and in control infants. He reported a pulmonary arteriole abnormality commonly associated with chronic alveolar hypoxia. This took the form of hypertrophy and hyperplasia of the smooth muscle fibres in the small pulmonary vessels. He During the past three years in Newcastle upon Tyne we have attempted to measure the size of the small pulmonary vessels in a series of infants, including a group of SIDS cases, and to quantify and compare the degree of hypertrophy or hyperplasia which may or may not be present. Material and methodsLung sections were taken from 90 infants and young children. These included 30 cases of the SIDS. The criteria for diagnosis of SIDS were the sudden death of an infant which is unexpected by history, that is, the infant was in apparently good health or gave a history of minor illness immediately before death, and in whom there is no clear and acceptable cause of death at the time of necropsy.The remaining 60 cases were divided into four groups. Group 1 comprised 15 infants who died as a result of acute respiratory illness of less than one week's duration and were presumably subjected to acute hypoxia during their terminal illness. Within this group were cases of acute bronchiolitis and acute lobular pneumonia. Group 2 comprised 15 481 on 11 May 2018 by guest. Protected by copyright.

The conducting tissue of the heart was studied in a group of 38 cases of the sudden infant death syndrome and in a control group of 28 children dying of known causes. A variable amount of fibrous tissue was found in the atrioventricular complex in almost every case. There was a statistically significant increase in fibrous tissue with age in both groups and there was also significantly more fibrosis in the sudden infant death group compared with the controls. Possible explanations for these findings are discussed and it is suggested that the results might be of aetiological significance in the sudden infant death syndrome.

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tinue to use celphaloridine as a local application in the proiphylaxis of potentially contaminated wounds. We are indebted to Glaxo Research Ltd. for the supply of cephaloridine (Ceporin) and Aspro-Nicholas Ltd. for the gentamicin (Genticin).-We are, etc.