My grandmother also believed in powwowing. She refused to go to a medical doctor when diagnosed with breast cancer in 1938 and went to a powwow doctor instead. She died at age 38.
The Pennsylvania German Society is publishing a new book on powwowing which is due to be released in August of this year. "Powwowing among the Pennsylvania Dutch: A Traditional Medical Practice in the Modern Word," by David W. Kreibel, will be Vol. XLI of the society's series of annual volumes. When it's available, you can order it directly from the society's Web site at
http://www.pgs.org/series.asp. If you join the society, you can get the book free as part of your membership. These are extemely well-written and well-researched books—well worth the money!