APRIL 25, 188+4.] 
in Paris, regarded as sufficiently clean, there 
was found, in the spring of 1882, 3,830, and, 
in the winter of 1882, 6,500; giving a mean of 
0,260 to the cubic metre. A comparison with 
the air of a room used for a study in the observ- 
atory at Montsouris showed, for the spring of 
1882, 270, and, for the winter of 1882, 380; 
giving a mean of 325 to the cubic metre. From 
this it at once appears that the air of the house 
in Paris was sixteen times as impure as that at 
Montsouris. The decrease in the number of 
germs from winter to spring is the reverse of 
what is observed out of doors, and is to be 
attributed to the more thorough ventilation 
during the warm months. 
The same relation was found in the air from 
hospitals, except that the numbers were very 
much higher ; varying from 4,500 in summer, to 
24,000 in winter, per cubic metre. The micro- 
cocci were found to be most abundant here; 
every hundred germs furnishing, on an average, 
ninety-one against five bacteria and four bacilli. 
The inoculation of these, however, was with- 
out result. 
The air and water from the sewers gave in- 
teresting results. A cubic metre of the former 
furnished from 800 to 900 microbes, while a 
litre of water taken at the point where it was 
discharged gave 80,000,000. In this relation 
it was found that a litre of water condensed 
from the atmosphere held about 900, a litre of 
rain-water 64,000, a litre of the Seine at Bercy 
4,800,000, while, after the river had traversed 
Paris, a litre was found to contain 12,800,000. 
From this it can be understood how easily 
stagnant water of a sewer can putrefy, and how 
essential it is that there should always be a 
current flowing to prevent this. In the air of 
sewers it is the bacteria proper which abound, 
but they were without effect when inoculated 
in animals. 
In the ordinary dust of houses it was esti- 
mated, after careful weighing and cultivation, 
that each gram contains about 750,000 spores. 
A sufficient number of analyses of the soil have 
not been made as yet, but those made give an 
average of from 800,000 to 1,000,000 for each 
gram of earth. In the deeper layers the bacilli 
preponderate over all other forms, while on the 
surface the micrococci are most abundant. 
Antiseptic substances are last considered ; 
and these are regarded as acting in two ways, 
_—first by destroying the bacteria already in 
activity, and, secondly, by preventing the ger- 
mination of spores. 
Of such substances, oxygenated water (H,O:) 
was found to be the most powerful, then solu- 
tion of corrosive sublimate and nitrate of silver. 
SCIENCE. 521 
After these come a long list of less efficacious 
ones. ‘The only compounds which were capa- 
ble of destroying germs in their dry state by 
means of the vapor given off were bromine, 
chlorine, hydrochloric and hyponitric acids. 
Such is a brief summary of the principal 
points touched upon in this book. It is not 
quite so clearly and concisely written as might 
be wished; but it is a valuable contribution to 
science, and must serve as a model for any one 
who undertakes work in this direction. <A care- 
ful perusal of the book itself is certainly to be 
recommended to all interested in the subject. 
MINOR BOOK NOTICES. 
Outlines of chemistry for agricultural colleges, public 
and private schools, and individual learners. By 
N.B. Wesster. New York, Clark & Maynard, 
1883. (Practical science series.) 8+144p. 24°. 
Tuts book seems somewhat out of place in 
a practical series, inasmuch as it consists chiefly 
of a collection of definitions and brief state- 
ments of common facts. 
The experimental side of the subject is 
almost wholly neglected, or, at best, is passed 
over with brief allusions. To the student who 
is receiving instruction by lectures, the work 
might be of some service as a partial relief in 
taking notes, or as a book of reference, though 
it is too limited in detail to be of general use 
in this direction; but, as a text-book in a 
systematic course of instruction in elementary 
chemistry, it must fall short of the author’s 
intention. 
The electric light in our homes. By Ropert Ham- 
MOND. New York, Worthington, 1884. 12+ 
18ehperpillustr.” 78°. 
Tus is a special pleading for the incandes- 
cent electric light, delivered by Mr. Hammond 
in the towns of England as he travelled, in 
the hope of awakening the English people to the 
fearful condition of their homes at present, on 
account of the harmful effects of the products 
of gas consumption. In the opening, Mr. 
Hammond is very careful to first heat his audi- 
ence over the gas-burners, then drench them 
with the condensed steam, and finally sprinkle 
them here and there with little specks of soot. 
After bringing his hearers into this unpleasant 
condition, a bright, clean, and cool incandes- 
cent electric light is held before their eyes till 
they fully appreciate its beauties. A short 
return is made to the drenching and warming 
process to make sure of any laggards, and the 
conditions of success of an electric-light sys- 
tem are explained. The story is well told 
