78 LECTURE III. 



we see it with our eyes. Many years, however, will elapse 

 before they will be used for scientific purposes; until then, 

 naturalists must agree to apply photography for ordinary 

 delineation, and the geometrical method for drawings which 

 are required to be comparable by measurement. 



Oasts, as well of living persons as of dried skulls, if they 

 are carefully prepared, may, in many cases, entirely supply the 

 place of the originals. In the case of nations who shave the 

 whole, or nearly the whole, head, complete casts of the head 

 may be taken from the living. The masks are generally less 

 useful than the casts of the head, as the forced positions of the 

 closed eyes and lips, as well as the unpleasantness of the con- 

 traction of the drying gypsum, contorts the features. 



It cannot have escaped you, that the various cranial measure- 

 ments by compass, measuring-tape, and rule, give but an 

 imperfect idea, and indeed only some of the principal dimen- 

 sions of the head. If both the exterior and interior of the skull 

 are to be represented completely by measurements of this sort, 

 a very great number of measurements must be taken, which 

 would be objectionable, owing to the necessary indefiniteness of 

 their terminal points. Other means had therefore to be contrived 

 to measure the internal capacity of the skull, with a view to the 

 formation of conclusions as to the development of the brain 

 and its component parts. The various substances used for 

 this purpose may be divided into two categories : such as 

 serve to indicate the capacity of the skull, irrespective of the 

 size and shape of individual parts ; and such as show this 

 shape and the proportion of the individual parts to each other. 

 Tiedemann closed the apertures of the cranium with wax, 

 placed it upon the vertex, and then filled the cavity with 

 millet seed, shaking them till they were at the level of the 

 occipital foramen. He then weighed them, and using them 

 for other similar measurements, he obtained weights which, 

 though comparable with each other, could not be adopted by 

 other observers, there being no certainty that the millet-seeds 

 used by them were of the same size or degree of dryness* as 



* Sand, of a recognised specific gravity, and carefully dried, is the sub- 

 stance most frequently employed in England. — Editor. 



