The deviation of man from the state in which he was originally placed by nature seems to have proved to him a prolific source of diseases.

I hope that some day the practice of producing cowpox in human beings will spread over the world - when that day comes, there will be no more smallpox.

I shall endeavour still further to prosecute this inquiry, an inquiry I trust not merely speculative, but of sufficient moment to inspire the pleasing hope of its becoming essentially beneficial to mankind.