I have duly recieved your favor of the 23d. and am happy to learn that you mean to favor the public with an account of the vaccine inoculation from your own experience, which I am persuaded will be highly useful. I think it an important object in such a work to bring the practice of the inoculation to the level of common capacities: for to give to this discovery the whole of it’s value, we should enable the great mass of the people to practise it in their own families & without an expence, which they cannot meet. to do this I concieve but a single point essential, which is to enable them to be sure that the matter is in a proper state; and I question if unexperienced people can be guided in this by any thing but the date, or distance of time from the inoculation at which the matter is always good. but is there such a point of time? I thought from my trials there was; but more extensive observations are necessary to ascertain that, and what the true point of time is. mr Vaughan had asked me to permit my letter to him to be published. my objection to it was that I am not a medical man, that it would be exhibiting myself before the public in a science where I might be exposed to just criticism, and that the observations of the medical gentlemen themselves would soon furnish what was better. if however the letter can be useful as a matter of testimony, or can attract the notice or confidence of those to whom my political course may have happened to make me known, and thereby engage their belief in a discovery of so much value to themselves and mankind in general, I shall not oppose it’s being put to that use. I will only ask that if there be any incorrectness of expression in it, open to obvious criticism, you will be so good as to rectify it. Accept assurances of my esteem and respect.