As an infant, he suffered from ill-health.
"I am in abundance of pain about our dear child: though I am convinced in my reason 'tis both silly and wicked to set one's heart too fondly on anything in this world, yet I cannot overcome myself so far as to think of parting with him with the resignation that I ought to do," the mother wrote from Middlethorpe at the end of July.

"I hope and I beg of God he may live to be a comfort to us both.

They tell me there is nothing extraordinary in want of teeth at his age, but his weakness makes me very apprehensive; he is almost never out of my sight.

Mrs.Behn says that the cold bath is the best medicine for weak children, but I am very fearful and unwilling to try any hazardous remedies.

He is very cheerful and full of play." "I hope the child is better than he was," she mentioned a little later; "but I wish you would let Dr.Garth know he has a bigness in his joints, but not much; his ankles seem chiefly to have a weakness.