According to Boswell, "the poor child was sickly" just after birth which took place in the early hours of November 15, 1776. He continued to be ill in the evening, sucking only a little. On the following day, he was attended to by Dr Thomas Young and surgeon Alexander Wood, the latter of whom thought the situation "so precarious that he should be christened without delay". The christening was performed at four in the afternoon by the Rev. Alexander Webster in the nursery, witnessed by Annie Cunninghame and by Boswell's clerk John Lawrie.
David's health gradually improved, and on February 17, 1777, Boswell sent off a long letter to Dr Johnson, in which he wrote that the infant's health was "much better than we could almost have hoped".
On March 29, however, the situation had worsened significantly, and Boswell wrote:
Poor little David had been very ill for some days of a teething fever which was very severe on his delicate frame. [...] I drank tea with Grange, but was called home before it was finished, the child having grown worse. I found him in sad distress, and his anxious mother in much affliction. I had not before been seriously alarmed for him, as he had struggled on wonderfully. But I was now affected to the heart, and to make my wife easy, I sent for Dr. Young. He bathed his limbs in warm water, which relieved him a little. But he was pale and feeble, though in as much pain as he apparently could suffer. [...] [H]e expired a little before nine.1
Over the next few days, Boswell described in some details the family's grief over the dead child. On March 30, he wrote:
This morning Veronica and Effie would see their little brother. Veronica calmly kissed him. But Effie was violently affected, kissed him over and over again, cried bittely, "O my poor billy David," and run to his nurse, who had also been hers, and clung about her, blubbering and calling to her, "O come and take him off the table. Waken him, waken him, and put him in his cradle."2
In the evening, Dr. Young and surgeon Wood performed an autopsy on the corpse, informing Boswell that "his bowels were not right, some of them being too tight and some too large, and that there were hardnesses in his lungs which would have grown worse, so that he could not have had a good life."
On March 31, Boswell "locked myself in the drawing-room with the little dead, and read the funeral service over him.", following which the coffin was brought to Duddingston and interred in the family vault of Boswell's friend Sir Alexander Dick.