ON COMPOSITE PHOTOGRAPHY AS APPLIED TO CKANIOLOGY. 113 



statements. During the few seconds taken to empty the skull it is hardly possible that some 

 water does not return from the sagittal, coronal, and squamous sutures to the cerebral cavity, but 

 I am satistied that it is an almost inappreciable amount. 



Does all the water which properly belongs to the cranial cavity drain out in fifteen seconds ? 

 I am certain it does not. If you fill Professor Eanke's bronze skull with water exactly according 

 to our directions, and empty it in fifteen seconds exactly according to our directions, you will find 

 that about 6 cubic centimeters are still retained. It cannot be maintained that the natural skull, 

 even wheu well varnished, will do better than this. If it ever becomes desirable in craniometry 

 that the true and exact cubic capacity of the skull must be ascertained, this quantity, or some other 

 quantity to be determined by experiment and computation, may be added to the amount in the 

 glass; but this small amount may perhaps be disregarded so long as science demands only "com- 

 parable values, collected under the same conditions and effecting among them afiQnities conformable 

 to reality."* 



Another objection brought forward by Dr. Topinard, and already quoted, is that " the water 

 wetting the sides of the glass rises on it, and one can be mistaken to the extent of 5 cubic centi- 

 meters." This would truly be a grave source of error if it were not so easily removed. Many 

 plans for remedying this difiiculty have been thought of, and the one we have recommended of 

 scattering some light powder on the surface of the water will, we hope, give satisfaction to all who 

 may try our method. 



One of the most important obstacles in our way to success in the early stages of our investiga- 

 tions — an obstacle not brought forward in this connection by Dr. Topinard — was this : The water 

 soaking into the walls of the skulls almost invariably causes them to expand and rapidly increases 

 their cubic capacity. Table III will illustrate this. But it will be seen that in twenty-one skulls 

 re-measured within five minutes, fourteen did not expand appreciably in that short time ; two 

 increased 5 cubic centimeters, three 10 cubic centimeters, and two 15 cubic centimeters, which 

 was the maximum. These were unvarnished. Among nine varnished skulls tried, the expansion 

 never exceeded 5 cubic centimeters in five minutes, and reached this only in three cases. There- 

 fore, I think we are j ustified in concluding that in forty-five seconds, the time allowed by our method 

 for filling a skull, the expansion from moisture is inconsiderable ; and it is siiecifled in our instructions 

 that before the next comparable measurement is made the skull shall be reduced by drying to its 

 former weight, and presumably to its former capacity. 



The amount of water which a skull will hold in its meshes is much greater than one would 

 suppose who had not made special investigations into the subject. Some idea may be gained of 

 the hygroscopic capacity of the skull by consulting Table IV; but this subject has received such 

 extensive treatment at the hands of Mr. Broca, in his paper already referred to, that it need not 

 be further considered here. 



One advantage of our method I conceive to be the elimination of much of the personal equa- 

 tion, which is such a disturbing factor in all other methods. There is little, if anything, left for 

 muscular exertion to alter. With our most imi^ortant operations the unchangeable element of 

 time takes the place of the fickle element of vital force. In the most popular of all systems, that 

 of Broca, the muscular action is chiefly limited to one part of the operation, that of ramming or 

 thrusting. But hear what Dr. Topinard has to say of the personal effort in this case: "The same 

 person * * * does not thrust the same, morning and evening, before and after meals, in think- 

 ing of his business or in giving his entire attention to what he does, in conversing, or in smoking 

 for stronger reasons, two persons at a distance from one another, who have not given an example 

 to one another, of different ages, one of sixty, the other perhaps young, one convinced of the at- 

 tention he must pay to the operation, the other having read the description and imagining that it 

 is very simple." 



For uniformity of results I think the figures shown in the accompanying tables (I and II, par- 

 ticularly the latter) have never been excelled by any method, and in considering these it must be 

 remembered, in favor of the system under which they were obtained, that it is new and seems still 

 capable of much improvement. 



• Topinard, op. cit., p., 591. 

 S. Mis. 154 15 



