ADMINISTRATIVE REPORT XCl 
from slain enemies; it is recognized by careful students that 
the primary motive in taking such trophies is thaumaturgic or 
necromantic, growing out of the belief that the strength, valor, 
or other qualities of the slain enemy will be magically trans- 
ferred to the slayer by this means. It has long been known, 
also, that in prehistoric times cadavers were trephined for the 
purpose of obtaining amulets. Now these and other facts 
have been brought together in a sequential order suggested 
by the development of beliefs, and it becomes evident that the 
operation of trephming was originally postmortem and thau- 
maturgic or magical. It seems highly probable that in the 
next stage the operation became antemortem, and partook of 
the nature of the ordeal, a form of divination characteristic 
of many peoples, which has extended into the present century 
even in civilized nations. From this stage it is easy to trace 
the history of the operation, the remaining stages being repre- 
sented among well-known peoples, primitive and advanced. 
The history of this branch of surgery, beginning with the 
mutilation of the dead and ending with the reconstruction of 
the living, is highly significant; it would be difficult to find a 
more striking case of the survival of modes of conduct despite 
transformation of motive. 
It is noteworthy that the prehistoric trephining of Peru 
blends with the shamanistic procedure of the North American 
tribes in such manner that each illumines the other. The 
significance of the Peruvian trephining could not have been 
ascertained without the knowledge of primitive ideation gained 
through study of the Indians of our own woodlands, prairies, 
and mountains, while certain symbolic features in.the cere- 
monials of the pueblo peoples can be interpreted only in the 
light of the information afforded by study of the Peruvian 
trephining. Thus the paper incidentally establishes the sub- 
stantial unity of the aboriginal people and aboriginal culture 
of the Western Hemisphere. 
THE CLIFF RUINS OF CANYON DE CHELLY, ARIZONA 
Perhaps the most important lesson learned through researches 
concerning the American tribes is that primitive peoples reflect 
their environment. Even the most casual observation shows 
