I took in my mouth some very strong wine-vinegar, and closing my
teeth; I gargled and rinsed them very well...but there were an
innumerable quantity of animals yet remaining in the scurf upon the teeth...
I took a very little wine-vinegar and mix it with the water in which the scurf was dissolved, whereupon the animals died presently. From hence I conclude that the vinegar with which I washed my teeth killed only those animals which were on the outside of the scurf, but did not pass through the whole substance of it.