Your favor of the 17th. arrived last night, together with the new Vaccine matter which was immediately sent to Doctr. Gantt. the 2d. as well as the 1st. supply of matter had failed. we hope the 3d. will be more succesful. how might it answer to put the matter into a phial of the smallest size, well corked, & immersed in a larger one filled with water & well corked. it would be effectually preserved against the air, and I doubt whether the water would permit so great a degree of heat to penetrate to the inner phial, as does when it is in the open air. it would get cool every night, and shaded every day under the cover of the stage, it might perhaps succeed. I leave this place on the 30th. inst. for Monticello, being unwilling to risk myself on the tidewaters during the months of Aug.1 & September, when situations which generate bilious complaints are most dangerous. my own is entirely exempt from that danger. should you be so good as to continue forwarding matter till it succeeds, it will now be best to address the packages to Dr. Gantt, from whom, so soon as he succeeds, I shall ask a transmission of fresh matter to Monticello,2 where I shall endeavor to introduce it. it will be a great service indeed rendered to human nature to strike off from the catalogue of it’s evils so great a one as the small pox. I know of no one discovery in medicine3 equally valuable. Accept assurances of my great esteem and respect.