"I shall please"

From Jerome Groopman's excellent (and highly readable) The Anatomy of Hope, a very elegant etymological summation and a note about the shift in how the use of placebos is understood by researchers:

The term "placebo," I learned from articles on the subject, is Latin for "I shall please" and is derived from the Catholic vesper service for the dead. In the past, paid mourners would participate in the service to pacify the grieving family.

Later he adds:

The inert placebo was meant to mute the background noise of the body processes, the random and supposedly meaningless oscillations that occur in our physiology. The outcome among the placebo-treated control patients was judged as the zero baseline and subtracted from the observed effects of the true therapy.

Recently, though, a number of scientists have questioned the assumption that placebos were inactive, contending that they have significant biological effects and...provide one of the clearest windows into the nexus between mind and body, particularly on how belief and expectation may affect pain and physical debility.