FACTS AND OBSEUVATIONS. 
407 
however, ozone loses its peculiar properties, probably enter¬ 
ing into combination with some of the constituents of the 
circulating fluid. 4. Animals can be subjected to the influ¬ 
ence of a considerable proportion of ozone in the air for 
hours without permanent injury; but in the end ozone pro¬ 
duces effects which may continue after its withdrawal, and 
destroy life /^—EdinhurgJi Medical Journal. 
Arsenic in Commercial Preparations of Bismuth. 
—Dr. Herapath has found that the presence of arsenic is 
almost universal in the bismuth of commerce; it hence follows 
that the medicinal compounds of this metal are often con¬ 
taminated with it. He proposes the removal of it by a simple 
process, namely, that of boiling the insoluble salts of bismuth 
with a sufiicient quantity of solution of caustic potassa or soda, 
which will quickly remove the arsenic in a soluble form. A 
repetition of this may be found necessary. 
London Well-water. —Dr. Letheby, in his report of 
the water-supply of the city of London, states that, from the 
water in the w^ells in the city being highly contaminated with 
organic matters, the poor have a wholesome dread of the city 
pumps, and resort to the drinking fountains instead. Of 
the thirty-six pumps in the city, there is hardly one which 
supplies a drinkable water. When examined in large volume 
it presents a deep sea-green tint from the quantity of organic 
matter dissolved in it, a quantity that in some cases reaches 
ten grains in the gallon; and the amount of saline matter is 
frequently above one hundred grains in the gallon. The 
nature.of both the organic and saline constituents indicates 
most unmistakably the source of the supply. It has its 
origin in the porous soil which is saturated with the soakage 
from sewers, drains, and graveyards. Almost every well, 
indeed, has its speciality. Those in the neighbourhood of 
the markets are known by the soakage from the surface 
ground; the pump in Leadenhall Market, for example, is 
enormously charged with common salt from the pickled hides, 
which are exposed for sale upon the ground of the market. 
It is time that the w^ater of the city pumps should be disused, 
except for the purposes of street cleansing, and that the fil¬ 
tered water of the drinking fountains should take its place. 
