Waterhouse continued to correspond with Jenner, and was regarded as his accredited representative in New England. Writing to Dr. Lettsom, 16th November, 1802, he says—
Dr. Jenner has just sent me a present I highly prize—a silver box inlaid with gold of exquisite taste and workmanship, bearing this inscription—
Edward Jenner to Benjamin Waterhouse.
But Mr. Ring annexed the superscription in rather an hyperbolical style—
From the Jenner of the Old World
To the Jenner of the New World.
Long will it remain among the sacræ relictæ of my family.[228]
Waterhouse was a man of an ingenious turn of mind. When troubled with ill-results from his operations at the end of 1800, he tried what has since been called retro-vaccination, probably for the first time. Here are his words from his letter to Jenner, 24th April, 1801—
I inoculated one of my cows with the Vaccine Virus, and obtained from her a crop of matter on the ninth day, which produced the disease in the human subject to perfection. Is this experiment known among you? As I operated myself there was no avenue opened for deception in the whole experiment.
A sentence which follows is too characteristic to be passed over. Says Waterhouse—