428 
COLOUR- TESTS FOR STRYCHNIA, ETC. 
original water will form gravel, and surface clay, and sand or 
soft limestone:—some, deeper and more altered, will show 
the effect of chemical action by unmistakeable chemical and 
atomic change, while the wealth of fossil organic remains 
still present, sufficiently speaks of their mechanical origin: 
others again, much deeper, will have been so completely 
altered as to have lost all trace of this life origin. It does 
not the less follow that they have once contained fossils as 
distinct and as numerous as in any recent deposit. 
As each rock comes again within the influence of surface 
disturbance, it will be again worn away by the river, or 
beaten into fragments by the tidal wave ; water will once 
more destroy what water originally formed, what water 
afterwards modified, and what will once more be converted 
into a deposit at the bottom of the ocean, the grand reservoir 
of the same ever present, ever active element. 
In all the great circle of changes concerning which geology 
informs us, water is then the chief agent. Heat and chemical 
action of themselves can do little, and certainly could not 
produce what is needed for our world. They act with and 
by water, and thus produce their results. 
Abstract this important form of matter and consider what 
the result would be. The great ocean would be but a salt 
desert without an oasis, the land a dry parched rock ; there 
would be no life, animal or vegetable, not even the smallest 
animalcule or the red lichen on the snow. The sky would 
be without cloud, and the thermic and magnetic currents 
would cease to vivify the dry bones that would then form but 
a skeleton of the earth. 
Water is the life of the earth as blood is the life of man. 
This is a wonderful and instructive analogy, and one w hich 
may lead to many useful suggestions in the contemplation of 
nature.— Condensed from the Chemical News . 
ON the colour-tests for strychnia, and the 
DIAGNOSIS OP THE ALKALOIDS. 
Being the substance of part of the Croonian Lectures for 1861, 
delivered at the Loyal College of Physicians. 
By William A. Guy, M.B. Cantab., Fellow of the College 
and Professor of Forensic Medicine, King’s College, London. 
(Continued from p. 242.) 
Assuming the description just given to be correct, T now' 
proceed to inquire whether there are any known substances 
