Professor D. Wilson on Ancient British Skull Forms. 51 
100,000 times its weight of water, and yet not be entirely 
dissolved. This, its slowness of solution, is probably owing 
to its comparatively high specific gravity, in consequence of 
which the oxide falls to the bottom, and to the strong co- 
herence of its particles, resisting its disintegration. What- 
ever the explanation may be, the property is a fortunate one 
for animal life; for were it readily soluble, were it more 
than very slightly soluble, how direful might have been the 
results! May we not view it as one of the many happy 
adaptations which are so common in the economy of Nature, 
and an instance of the limitation of the noxious, or its 
neutralization, or even more, of its transition into positive 
good ? this last, on the supposition that arsenic used in a 
very minute quantity may really be beneficial. 
lllustrations of the Significance of certain Ancient British 
Skull Forms. By Danizrt Witson, LL.D., Professor of 
History and English Literature, University College, 
Toronto. 
During a recent visit to Washington, I availed myself of 
the facilities afforded me by Professor Henry, the learned 
secretary of the Smithsonian Institution, to examine with 
minute care the ethnological collections preserved there, 
including those formed by the United States Exploring 
Expedition ; and especially a highly interesting collection 
of human crania. The latter includes those of Esquimaux 
and Tchuktchi, a number of compressed and greatly distorted 
_ Chinook and other Flathead skulls, as well as examples of 
those of other Indian tribes, both of North and South 
America ; and of Fiji, Kanaka, and other Pacific islanders. 
On my return I spent a short time in Philadelphia, chiefly 
for the purpose of renewed study of the valuable materials 
of the Mortonian collection ; and while there enjoyed the 
opportunity of examining, in company with Dr Aitken 
Meigs, a series of one hundred and twenty-five Esquimaux 
crania obtained by Dr Hayes in his Arctic journey of 1854. 
The materials for craniological investigation which such 
collections supply can scarcely be surpassed in some of their 
