MUNIZ—MC GEE | MANIPULATIONS OF THE OPERATORS 55 
METHOD OF OPERATING 
The twenty-four or more operations exhibited by the nineteen crania 
reveal clearly and conclusively the methods pursued by the operators. 
On reviewing the operations, it appears that the methods were simple, 
comprising three types of manipulation, which were combined in many 
instances, probably in all of the completed operations. These types 
are (1) incising, (2) elevating, and (3) rasping (i. e., grinding, filing, 
or scraping away the bone by a rough-surfaced or irregular-edged 
instrument). 
The incising was of two fairly distinct but intergrading subtypes, 
(a) rectilinear and (/) curvilinear. All of the incisions, so far as 
clearly revealed, both rectilinear and curvilinear, are essentially similar 
in form; they are V-shape in section and canoe-shape in plan, broadest 
and deepest toward the middle, where alone they penetrate the bone, 
shallowing and narrowing toward the extremities, which frequently 
project beyond the margin of the aperture. The rectilinear incisions 
are frequently, and the curvilinear cuts commonly, more or less oblique 
to the tangent plane passing through the point of cutting. 
The rectilinear incisions are well displayed in several specimens, 
either combined in such manner as to describe quadrilaterals, as in 
crania 1, 2, 3, and 4, or less regularly disposed, perhaps, about the 
margins of depressed fractures, as in crania 5, 14, 15, and 19, or else 
distributed at random as in crania 1 (the outlying incision), 16, and 17, 
in addition to the many examples of minor cutting or scratching 
described as exploratory. 
The development of rectilinear incision into curvilinear cutting is 
well illustrated by several examples. In cranium 4, three of the six 
incisions became curved in consequence of the oblique attitude in 
which the instrument was held by the operator in its passage across 
the spherical surface of the skull, and a fourth incision was strongly 
curved toward one of its extremities, evidently because of deflection of 
the instrument by the superciliary ridge; and one of the random cuts 
in cranium 16 is curved at both extremities, by reason of rugosities of 
the surface of the bone, in such manner as to assume a somewhat 
curvilinear form. In other cases the incisions were evidently curved by 
studied effort, as most clearly shown in cranium 6. In this ease it is 
clear that the operator began with a rather short vertical and reeti- 
linear incision, which was in one direction developed into a curye, 
partly by lateral deflection of the instrument at one end of the recip- 
rocal stroke, partly by holding it more obliquely as the cutting pro- 
ceeded. Of like significance are the partly rectilinear partly curvilinear 
incisions displayed in crania 7 (the later operation), 18, and 19; while 
in still other cases, in which the marks of instrumentation have been 
obscured by subsequent rasping or obliterated by reparative growth, 
the form of the aperture suggests a similar combination of rectilinear 
