50 PRIMITIVE TREPHINING IN PERU [ETH. ANN. 16 
The specimen displays three extensive operations of different dates, 
without trace of antecedent lesion in any case. The earliest operation 
was located in the upper portion of the left parietal, adjacent to the 
sagittal suture, centering about 60 mm. back of the coronal; it resulted 
in arudely circular aperture now measuring 29 mm. in longest diameter. 
Save that the margins are beveled from without, no trace of instrumen- 
tation remains; the beveled surface has assumed the texture normal to 
the exterior of the cranium save for radial lines of reparative growth, 
increasing in strength toward the edges of the aperture. Many strong 
spicules and knobs of new bone project from the margin, sometimes 
so much as 3 or 4 mm. into the opening, while the diploe is completely 
obliterated. The extent of reparative process indicates that the patient 
survived the operation for years. 
The second operation centered 45 nm. below the first, i. e., near the 
posterior angle of the left parietal, about 42 mm. from the sagittal 
suture and 35 mm. from the middle line of the lambdoid. It resulted 
in arudely circular aperture now about 25 mm. in mean diameter, in every 
respect comparable with that of the first operation, save that the rep- 
arative modification of the bone is less advanced, especially about the 
upper margin or toward the antecedent opening. The beveled surface 
shows ridges of growth, but otherwise approximates the aspect of 
the normal bone, and appearances indicate that the periosteum was 
developed over it in quite the normal manner. The diploe is almost 
wholly obliterated, though it can be detected about the antero-inferior 
margin of the aperture and also toward the junction of the sagittal and 
lambdoid sutures. While spicular growth is in general less developed 
than about the earlier aperture, it is particularly well displayed about 
the inferior margin, where the spicules are at least 2 or 3 mm. in length 
and sometimes branch or divide into lateral spicules toward the extrem- 
ity. There can be no doubt that the individual survived this operation 
also for some, probably several, years, and it is possible that the two 
were performed about or (just possibly) at the same date. 
The third operation was located in the crown, involving the coronal 
suture, and traversing the sagittal suture near its anterior extremity. 
In this case fairly definite traces of instrumentation appear. The 
clearest marks are of such character as to indicate that they were 
produced by curvilinear incision effected through the use of a blunt 
single-point instrument wielded by a vigorous hand; and they are so 
related in position as to suggest that the operator (being right-handed 
though somewhat ambidextrous) sat on a low bench or bank, holding 
the head of the patient (lying supine and facing in the same direction 
as the operator) somewhat inclined forward between his knees; that he 
then began a curvilinear incision on the right side, swinging his hand 
strongly toward the left at the forward end of the stroke as the cut 
was extended and deepened; and that he gradually, with the use of 
the left hand or both together, carried the incision around to the left 
and then toward himself, in such manner as to describe an inverted U or 
