48 JOURNAL OF SCIENCE. 
On 
from greater depths than the service-water, they are generally cooler. 
Frequently, too, they are used for years, and many who use them 
continue in good health. There are, of course, in every community, 
many who are able to resist bad influences. They furnish no evidence 
for or against the danger of using bad water. The influences are 
felt principally by the weaker members of a community. 
As regards the specific objections which may be raised to using 
the water of city wells, it may be said, in the first place, that the 
evidence is pretty clear that water contaminated with sewage does at 
times give rise to low fevers. Though it is difficult to furnish satis- 
factory proof of the statement that the use of contaminated water 
tends to lower the general condition of health of those who habitually 
use it, those who have paid most attention to the subject unanimously 
agree that pure water is as important as pure air for the preservation 
of good health. One of the chief dangers in the use of water con- 
taminated with sewage is, that, by establishing connection between 
the sick and the well, it contributes to the spread of some forms of 
epidemic disease. As is well known, it is now held by many of the 
highest authorities that in some diseases the organisms which are 
believed to be the active causes are given off from the patients with 
the alvine discharges. If, now, by any means, these organisms or 
their germs are introduced into the system of a person in good health, 
the diseased condition is set up. What more efficient method of dis- 
tributing these organisms than drinking water which is contaminated 
with the contents of cesspools! Exactly what forms of disease may 
be spread in this way, it is difficult to say; but there is strong 
evidence in favour of the view that typhoid-fever and cholera are 
among them. Over and over again, outbreaks of typhoid-fever have 
been traced with practically absolute certainty to the use of water 
known to be contaminated by sewage. In regard to cholera, the 
evidence is quite sufficient to justify the destruction of ail city wells. 
Tra ReEMSEN. 
MICROSCOPICAL INVESTIGATION OF SOME 
 ERUPTIVE ROCKS FROM BANKS’ 
PENINSULA, N.Z. 
> 
BY PROFESSOR B. KOLENKO, OF STRASSBURG (ALSACE). 
From the ‘* Neues Jahrbuch fiir Mineralogie, Geologie und Palxontologie” for 188%.. 
Band I. p. 1. 
The material for this investigation was kindly given tome by 
Professor Cohen who had obtained it for the Petrographic Institute 
of the University of Strassburg from Mr. Schneider of Basel. As the 
specimens came from Dr. von Haast, the localities are absolutely 
trustworthy, and therefore the investigation of a collection of material 
not made by myself is in this case quite justifiable. 
Banks’ Peninsula is about 31 miles long by a maximum breadth 
of 20 miles and lies on the eastern side of the South Island of New 
