Case Report KH, a boy, aged 7 months 3 weeks, was admitted to King's College Hospital on April 22, 1947. Birth had been normal (birth weight 63 lb.) as also was development until six weeks before admission. The infant was vaccinated at the age of 2 months. He was breast-fed entirely for six weeks, then complementary feeding was begun. The baby's behaviour was normal until six weeks before admission when he stopped crying, lay very still, and slept for long periods, only waking when disturbed. He did not suck and had to be fed by spoon. Sweating was increasedduring this period. He had had no specific fevers. There was one sister aged 10. At the onset of the baby's illness this sister was at home with a cold, sneezing and coughing a good deal. On examination it was seen that the general nutrition was good, the skin normal, and the mouth and throat healthy. There was no glandular enlargement, and no palpable enlargementof liver or spleen. There was no abnormality in heart or lungs. The pupils were small with no reaction to light, or appreciation of light; ophthalmoscopy showed a bilateral optic atrophy, with normal maculae and retina. The infant appeared to be deaf. No other abnormality was observed in the cranial nerves. Both upper and lower limbs were markedly spastic. Reflexes were not obtained. There were bilateral extensor responses.

Investigations.-Lumbar puncture was performed on April 22 and 10 ml. fluid removed under increased pressure. Analysis showed cells 2 per c. mm.; protein 30 mg. per 100 c. mm.; globulin, negative; sugar present; chloride 740 mg. per 100 c. mm. Lange curve 01 1000000; Wassermann reaction negative. On April 23 a radiograph of the chest showed no abnormality.