Th: Jefferson presents his compliments to Dr. James Mease and his thanks for his very learned and ingenious dissertation on canine madness. He had not before heard of the method of prevention by the use of water in a stream as mentioned on page 103, the theory of which appears probable and the application easy. He has lately had a letter from Algiers informing him of the cure of one of our captives there by a very strong use of Mercury, as recommended pa. 125. Whether the disease were real or not, it shews that this opinion is favored by the Arabic school of medecine, if we may use the expression. He has often thought that in order to discover some certain method of treatment of a disease, the most distressing of all those to which we are liable, it would be practicable and well worth while, to confine in a safe place a number of animals, communicating the disease successively to them, and subjecting them to various treatments till some one should be found the success of which might be relied on. The experimentalist who should be succesful in establishing by multiplied trials a certain method of cure, would merit an altar.