1. A case is described of the marble bone disease of Albers-Schönberg in a woman of forty-one who died from subarachnoid haemorrhage. Several congenital abnormalities were present.

2. No significant abnormality of the chemical composition of the bones was discovered.

3. The long bones were more resilient, stronger, softer and of higher specific gravity than normal and the abnormal compact bone of the skull was less resilient, weaker, harder and of about the same density as normal bones.

4. The simple investigation of determining the breaking strength of cortical bone yielded results similar to the more complex investigations and if applied to a larger series of cases could provide sound data on which to base speculations about this condition.