Monticello Aug. 4. 05.
Your favor of July 13. was recieved at this place. not being myself a competent judge of the analogies between the Cowpox, the small pox, the plague, & yellow fever, I readily acquiesce in the opinions of those who are the proper judges. that the Cowpox prevents the small pox is now I believe doubted by no body. but I had not supposed it to be established that it is a preventative against the plague. some paragraphs in the newspapers indeed had stated such a doctrine. but their editors admit falsehood with so much levity that a fact is not the more to be believed for being found in them. it may however be true altho’ it is in a newspaper. with respect to the experiment whether Yellow fever can be communicated after the vaccine, which you propose should be tried on some malefactor, no means of trying that are likely to be within my power. during the term I have been in office, not a single conviction in any capital case has taken place under the laws of the general government. the Governors of the several states would have it most in their power to favor such an experiment.
Having been very little in this state during the last 20. years and, when in it, scarcely ever absent one day from my own house, I am not sufficiently informed to answer your enquiries relative to the present state of the breed of Arabian horses here. I should judge from the little I see, that it is nearly in the same state in which it was when I knew it better.— altho’ we have had a few horses here said to be Arabian, yet our main stock of that race has been & still is drawn almost entirely thro’ England. Accept my salutations & assurances of great respect.
DLC: Papers of Thomas Jefferson.