OSTEOMETRY; THE MEASUREMENT OF THE BONES 59 



etc. It is quite possible, however, to find with the needle of the diagraph 

 certain essential points upon the lateral surface, and thus to indicate 

 1 hem also upon the craniogram. By thus locating porion and orbitale, for 

 instance, the FH may be drawn in upon a craniogram, often a great 

 advantage in getting relationships; while by drawing lines from these 

 points to those upon the outer contour, certain unexpected new lines and 

 angles may be formed, some of which may be found to be of much service. 

 When a craniogram is made from a skull properly oriented within a cubic 

 craniophore, a tracing of the frame of the craniophore, drawn about the 

 craniogram, will serve to orient it, and, if either one of the points that are 

 used in the determination of the FH be present, this important horizontal 

 may be added. 



Measurement of the Cranial Capacity. This procedure, No. 24 of the 

 prescriptions of 1906, is a very old one, and developed early in cranial 

 investigation. It consists essentially in first filling the entire cranial 

 cavity with some material consisting of small, dry, granules, and then 

 measuring it accurately by pouring it out into a graduated glass cylinder. 

 There are, however, many chances of error in this procedure, which have 

 been so far as possible eliminated by various devices. 



In the first place the larger orifices of the skull, except the occipital 

 foramen, which is left for filling and emptying, are plugged with cotton, 

 taking care not to allow the cotton plugs to project into the interior. The 

 material to be used in measuring is then poured in by means of a tin 

 funnel, the skull being held with the occipital foramen uppermost. 

 For filling material different investigators have employed sand, mustard 

 seed, canary seed, peas, small shot (No. 8), glass beads and other things. 

 Recently attempts have been made to use a liquid, water or mercury, in 

 conjunction with a thin rubber bag, which expands as filled, and assumes 

 the shape of the cranial cavity, and in the prescription of 1906 water is to 

 be used "whenever possible." A liquid has the decided advantage of 

 being non-compressible, and thus of occupying the same space in the 

 measuring cylinder as in the skull, insuring an exactness of result not 

 possible with the dry media, which can be compressed to a considerable 

 extent. 



Naturally a dry medium has in practical application a decided ad- 

 vantage over a liquid, and the chance of error through a different amouut 

 of compression in skull and cylinder has been reduced to its lowest terms 

 through an improved technique. Perhaps for general purposes some 

 small seed is the best, and of the various possibilities millet-seed, as re- 

 commended by Martin, is the best of all. This seed, not always easy 

 to obtain in the United States, is lenticular, not spherical, and has a very 

 smooth coat, and thus packs closely together, the individual seed 

 slipping into place very easily. Mustard seed is also good, but the 

 spherical seeds do not pack so completely, and the coat is not as smooth 

 as millet. 



