My dear Sir

I am much obliged for the Belfast Journal, which I will look to. It is, I believe, almost impossible to answer your question.— “what makes an Individual?”¹ Naturalists are generally agreed to look at all the members produced by one act of sexual generation as belonging to the same individual, but this definition will not apply to some of the lowest organisms which multiply by self division, but not as far as known by sexual generation.² How it is that a single cell, or a very few cells, suffice to give rise to a new organism will never be known until we can say what life is, and we are at present a long way off this goal. I wish I could have answered your question better.

Dear Sir | Yours faithfully | Chas. Darwin

J. Torbitt, Esq. | Belfast.