It may be that the premature death of the mother's children has some significance in connection with Oscar's phenomenal development.

There is certainly a hypernutrition of the parietal brain with atrophy of the optic tract, both of which conditions could arise from abnormal vascular causes, or the extra growth of the auditory memory region may have deprived of nutrition, by pressure, the adjacent optic centers in the occipital brain.

The otherwise normal motion of the eyes indicates the nystagmus to be functional.
"Sudden exaltation of the memory is often the consequence of grave brain disease, and in children this symptom is most frequent.
Pritchard, Rush, and other writers upon mental disorders record interesting instances of remarkable memory-increase before death, mainly in adults, and during fever and insanity.

In simple mania the memory is often very acute.

Romberg tells of a young girl who lost her sight after an attack of small-pox, but acquired an extraordinary memory.