[8]
stage of improvement. The scab, dossel of, and the thread impregnated with variolous matter and bound up in a gash in the arm, have been laid aside.
We are indebted to Mr. Sutton for the mode of communicating it by a slight puncture with the point of a lancet, or needle, dipt in fresh matter. As it is difficult sometimes to procure matter in a fresh state, I have been led to use it with equal success by preserving it on lint in a box, and moistening it with cold water just before I used it. Matter may be kept in this way for a month without losing its infectious quality, provided it be not exposed to heat or moisture. The former destroys its power of infecting as certainly as the salt of tartar destroys the acidity of vinegar. Moisture, by remaining long upon the matter, probably destroys its virulence by subjecting it to fermentation. The longer matter has been kept in a general way, the longer the distance will be between the time of communicating the disorder and the eruptive fever. It will be proper always to yield to the prejudices of our patients in favour of matter taken from persons who have but few pustules. But I am persuaded from repeated observations, that the disease is no ways influenced by this circumstance. I am satisfied likewise that there is no differ-
