432 NATURAL SCIENCE. Jone, 
Twelve pennies were left four days in twelve litres of water, which 
then had a slightly metallic taste, and the Sfivogyva plant died in it 
in one minute. The water generally used in experiment had been 
only one-fifth or one-tenth so strongly oligodynamic. Indeed, one 
part of copper in one thousand million parts of water may be fatal 
to Spirvogvra cells. |The copper went into solution as cupric hydrate 
combined with carbonic acid. Other metals, silver, zinc, iron, lead, 
mercury, acted similarly. The salts of these metals could also render 
water oligodynamic, and the vessels that had contained the solutions 
retained oligodynamic power, though to a less marked extent. 
According to physicists, the saturation of a solution depends on 
the quantity of substance that a definite quantity of water will take 
up; as the solution becomes supersaturated, equilibrium is restored 
by the redeposition of the substance. The molecules of a barely 
soluble body tend to attach themselves to some other substance, and 
so pass out of solution. Thus copper, in water which contains 
carbonic or other acid, gives off its molecules slowly but continuously. 
These spread through the water, some attaching themselves to the 
wall of the vessel. As complete saturation is reached, still more 
molecules adhere to the walls. Should the copper be removed before 
this stage is reached, the water withdraws some of the molecules 
from the wall and an equilibrium is established between the copper 
layer and the solution. If such a solution be poured into a clean 
glass, a layer of copper molecules is again deposited, and the greater 
area of wall offered, the more molecules will be attracted from the 
solution. 
In this lies the explanation of the neutralising effect of the 
various bodies above-mentioned. They simply attracted the metallic 
molecules. When oligodynamic water was well shaken up with 
powdered sulphur, and filtered, it was rendered completely neutral, 
and thus also sugar or salt failed, as they themselves pass readily 
into solution. 
As to the action of gum, albumen, etc., Nageli explains it on 
his own ‘‘ micellar” theory of the structure of organised bodies, of 
the truth of which he finds here additionai evidence. He considers 
that organised bodies are built up of micelle, invisible crystalline 
bodies, formed by the aggregation of chemical molecules, and that 
colloid substances form with water ‘‘ micellar solutions”; the copper 
molecules attached themselves to the micelle as they would to larger 
bodies. The Algze themselves acted as neutralising ayents when 
their number was in excess, and in this case the molecules could only 
act very slowly or not at all. 
Metallic substances would, in the same way, be removed from 
lakes, rivers, etc., by the presence of large quantities of insoluble 
substances. 
The water used in the experiment was supplied by the town 
(Munich). It was conducted through lead pipes terminating in the 
