XC BUREAU OF AMERICAN ETHNOLOGY 
rational etiology. In many respects the history of practical 
medicine and surgery exemplifies the history of sophiology. 
As pointed out in the accompanying paper, trephining, 
although one of the boldest operations of modern surgery, is 
in certain regions more characteristic of primitive culture than 
of civilization. In different countries students have been sur- 
prised at its prevalence and the apparent recklessness with 
which the operation is performed by skilless shamans for 
apparently trivial reasons. Perhaps the best figures for deter- 
mining the ratio of frequency of trephining are those afforded 
by the Muniz collection of over a thousand crania, of which 
2 percent are trephined, several more than once, so that the 
ratio of operations to individuals is almost exactly 2.5 percent; 
a ratio probably higher than that of modern hospital practice 
in any country, and many times higher than that of general 
practice. It may be observed that there is nothing to indicate 
Vitiation of this ratio by the selection of trephined crania and the 
rejection of entire skulls on the part of the collector, since Dr 
Muniz’ collection was made for general scientific purposes, so 
that all of the observed mummies were retained, and sinée, in 
most cases, the operation was not detected until the crania 
were subjected to critical examination in the laboratory. The 
frequency with which the operation was performed would 
indicate that, if it were surgical in the modern acceptation of 
the term, a high degree of surgical skill must have existed 
among the ancient Peruvians; and the fact that there is no 
indication of skill in the crude cutting awakens a suspicion 
that the Operators were not surgeons in any proper sense, and 
this despite the ready inference from about a third of the 
specimens in which the operations were evidently located by 
antecedent injuries. On critical examination of all of the 
specimens, the suspicion is confirmed and grows into a con- 
viction that the ancient operators were nothing more than 
primitive practitioners occupying the same culture grade as 
the shamans or ‘‘medicine men” of the North American tribes. 
The discussion of trephining in general is noteworthy in 
that it indicates with strong probability the course of develop- 
ment followed by this branch of surgery. It has long been 
known that savage warriors take sealps and other trophies. 
