Sir.—Dr. Schmitt's suggestion "that physical abuse was the actual cause behind the subdural hematomas in several of the six cases reported" by us is speculative. We looked carefully for evidence of abuse in each of these children, since the battered child syndrome and shaking injuries are well known to us. Dr. Schmitt's suggestion that the intervening mechanism "is apparently mysterious" is also speculative. We clearly stated that the mechanism is unknown to us and refused the temptation to offer an explanation for which we had no objective evidence. It does appear, however, from the substance of his letter that he has information concerning the definite mechanism for the production of subdural hematomas, since he states that "'spontaneous subdural hematoma' is no longer an acceptable diagnosis." If so, that information should be published.
The patient in case 3 was not 4 years old but 4 weeks old (this was