932 
FACTS AND OBSERVATIONS. 
have been made by Mr. Charles Heisch, the bearing of which 
is to simplify very much its qualitative analysis. A manu- 
facturer of lemonade, finding suddenly that he could not 
keep his beverage more than a day or two, and unable to 
understand the reason of this, called in the aid of Mr. Heisch. 
The mischief was traced to the water, and it was afterwards 
discovered that an almost inappreciable quantity of drainage 
had reached the well which was being used. Following up 
this clue, Mr. Heisch believes he has discovered a method 
whereby sewage, almost in the smallest possible quantity, 
may be traced in water. Six drops of clear sewage were 
mixed with 10.000 grains (rather more than a pint) of West 
Middlesex and New River water. To six ounces of this 
mixture ten grains of pure sugar were added. The same 
quantity of sugar was also added to six ounces of w T ater 
without any sewage. In from twenty-four to sixty hours 
the first mixture became turbid, and revealed in the micro- 
scope certain forms of cells, grouped in a manner which Mr. 
Heisch regards as characteristic. The water without sewage 
remained clear and sweet. One drop of fresh urine in 
10,000 grains of water yields a mixture which will keep for 
several weeks, but the addition of sugar will induce the ap- 
pearance of these cells in from twenty-four to forty-eight 
hours. Mr. Heisch states that filtering through the finest 
Swedish paper did not remove the germs, nor was boiling 
for half an hour any more effectual. Filtration through 
charcoal seems alone to have been found capable of removing 
the impurity. — Journal of the Society of Arts. 
A Test for Water in Milk. — It is, as is well known, 
a remarkably difficult matter to detect w T ater in milk, so as to 
say for certain that it has been added. A test which appears 
likely has been devised by Dr. A. E. Davies, F.C.S. Such a 
test, he believes, we have in the specific gravity of the serum, 
or liquid portion of the milk, from which the caseine and fat 
have been removed by coagulating and straining. The gravity 
of this liquid he has found to be remarkably constant, 
ranging, in that obtained from genuine milk, from l*02fi to 
1*028 ; and, by carefully ascertaining the specific gravity of 
the serum of genuine milk diluted with various quantities of 
water, we may obtain a standard of comparison which will 
enable us to say, within a few per cents., what quantity of 
water has been added to any sample of milk that may come 
under our notice. — Chemical News . 
The First and Second Stages of Labour. — In 
regard to this point, a very able paper was contributed to the 
