THE excellent results which are obtained from the use of spinal anaesthesia may be judged from its popularity in practice. From time to time, however, there have appeared in the literature reports of patients who have developed neurological complications-varying from headache, meningism, cranial nerve paralyses, and focal cerebral lesions to radiculomyelitis, cauda equina, and peripheral nerve lesionsoccurring immediately after or remotely following the administration of a spinal anaesthetic. The statements in the literature are extremely contradictory as to the frequency with which such nervous sequelae occur. Jarman14 gives the incidence of paralysis as one in ten thousand cases. Foss and Schwalm12 stated that they had never seen the slightest evidence of peripheral neuritis or sensory or motor disturbance following three thousand spinal anaesthetic administrations. They had never seen a case of foot-drop or had patients who suffered from pain in the body or in the legs following anaesthesia. These authors quote Lundy as never having noticed at the Mayo Clinic that sterile procaine hydrochloride administered by the usual technique and in safe doses produced any serious changes in the spinal cord. Lundy, Essex, and KernohanYz0 however, stated that they had observed a case of (' temporary paralysis " from the use of 10 per cent procaine.On the other hand, Hyslop13 reported neurological sequelae in 11 of 2074 cases recorded by various writers ; and 7 examples of neurological complications were reported by Brock, Bell, and Davison.' There is no doubt about the frequency with which severe and continued headache and also sixth-nerve paralysis occur. Indeed, BlattY5 in 1929, collected over roo cases of the latter following spinal anaesthesia. Loeserl9 believed that an inflammatory syndrome affecting isolated peripheral nerves was more frequent than was realized, having encountered 5 cases in one year. A review of the literature and the personal experiences recorded by Macdonald Critchley8 suggest that neurological complications occur much more frequently than is commonly supposed.In this paper are recorded 14 cases which developed a cauda equina syndrome following the administration of a spinal anaesthetic. Thirteen of these cases occurred within a period of twenty months. Only sixteen examples of this lesion were found in an examination of the literature before this period.This report is published not with the intention of disparaging a very valuable, if not indispensable, form of anaesthesia, but in the hope that the result of these