In 1760, Morgagni published some rather pertinent views on the subject of hydrocephalus. Among his many speculations appears one that is singularly appropriate:1
Indeed the greatest part of observers do not allow the disorder to be a hydrocephalus when the head is not enlarged. Yet there is not the least doubt, but that when a large quantity of water is by degrees collected in the cranium, a tumor of the head must infallibly arise therefrom, if it were possible for the bones to yield to the extension, as they do in young creatures: nor can it be doubted, but some of the causes, which give rise to the congestion of water in the heads of tender infants, are the same that give rise to the congestion in adults.... Suppose, for instance, either such a structure or constitution of the pineal gland, that it can transmit no water.
PARKER HL, KERNOHAN JW. STENOSIS OF THE AQUEDUCT OF SYLVIUS. Arch NeurPsych. 1933;29(3):538-560. doi:10.1001/archneurpsyc.1933.02240090108007