94 
NATURE 
[SEPTEMBER 25, 1913 
An interesting claim made is that the use of hard 
water causes visceral retention of uric acid. The 
rheumatism of peasants using but little meat in 
certain districts of Ireland, Wales, and Scotland 
he attributes to the abuse of tea, and in a lesser 
degree to exposure to cold. In referring to the 
“frugivorous teeth” of man it is suggested that 
the proneness to decay may be in the nature of a 
penalty for attempting to use these as “carni- 
vorous” organs. No mention is made here of 
the dentists’ opinion that the essentially decay- 
producing foods are those “claggy” with local 
acid fermentation to follow, e.g. the bun and 
glass of milk at night. 
(2) This work will appeal especially to the 
engineer, as the author has endeavoured through- 
out to give the data and laws required in design- 
ing to any specification. Following American 
practice, very low outer temperatures are reckoned 
with, such as 0° F. as lasting some days. 
The temperatures set forth as optima for various 
kinds of room are higher than those in use in this 
country. Thus a hospital ward is taken at 72°F., 
and rooms, offices, and laboratories at 70°F. 
Chimneys—other than furnace-flues—appear to be 
unknown, implicit reliance being placed on a com- 
bination of air warming with induction or exhaus- 
tion methods. 
The section dealing with the flow of air in ducts 
is well considered, and the anemometer is recom- 
mended for velocities not exceeding 1500 ft. per 
minute. After reviewing the Pitot, Venturi, and 
orifice devices the author mentions a novel and 
ingenious method depending on the increased tem- 
perature found after using a known amount of 
electrical energy, and so from this arriving 
at the mass of the air so warmed. 
The criterion adopted for purity of the air is 
the old chemical standard of carbonic acid, where, 
taking 4 per 10,000 as low, 11 as causing oppres- 
sion, 7 is taken for those ill, and 15 permissible in 
a group of healthy persons. An_ estimation 
apparatus in portable form, adapted for accurate 
work with small amounts of air, is illustrated and 
described, and appears likely to give good results 
as the pressure correction is simple and delicate. 
Humidity has to be considered where air is 
artificially warmed, and various forms of apparatus 
are shown, though the hot-air system outlined at 
the commencement appears to have none. Prof. 
Greene points out the objectionable features of | 
both extremes, but does not realise how, to English 
ways of thinking, the dryness is usually overdone. 
He points out a weak point in Mason’s hygro- 
meter, namely, its inaccuracy in still air, but the 
sling instrument shown does not impress one as 
practicable for average observers. 
NO. 2291, VOL. 92] 
The discussion of the wet-bulb temperature and 
its cause for exceeding the dew-point is lucid 
and interesting. Carrier’s work showing the 
mode of warming the wet bulb by heat rendered 
sensible is quoted briefly. After alluding to the 
disturbance of the mucous membranes by exposure 
to air itself too dry, no reference is made to the 
well-known feelings of malaise and depression 
brought about by life in a system of manipulated 
air monotonous in character. No matter what 
may be the carbonic-acid content, the normal 
cutaneous stimulus is lost. et 
(3) The author of this monograph is the 
technical director of a large American electro- 
chemical company. The work falls into two por- 
tions: (1) The text—in which is a general descrip- 
tion of the substance and its mode of action. This 
is continued by accounts of six main applications to 
public health work, thus: Water purification, 
sewage disinfection, street flushing, medical and 
surgical uses, agricultural, house-fly campaign 
(68 pp.). (2) A series of summarised references 
and reports dealing very fully with American 
practice, but which also includes many quotations 
from English publications (154 pp.). 
The mode of its action being essentially that of 
oxidation is well stated, and the confusion with 
chlorine preparations pointed out. 
The relative unsuitability of copper sulphate 
additions to polluted water destined for anima 
consumption is well brought out in the account of 
the Chicago stockyard and the sewage-contamin- 
ated waters of Babbly Creek. The animals 
were found to thrive less than when allowed 
to drink city water. The change was made 
to hypochlorite treatment, with the result 
that a purer water organically was obtained than 
from the city mains by some thirty-seven times 
less B. coli frequency. 
Limits to the powers of hypochlorite are given 
on pp. 22 and 23. But though small in quan- 
tity, it should be clearly shown that some increase 
in hardness is inevitable in the water treated by 
it. 
The volume concludes with an admirable index 
arranged separately under subjects and names. 
OUR BOOKSHELF, 
The Under Dog: a Series of Papers by Various 
Authors on the Wrongs Suffered by Animals at 
the Hand of Man. Edited by S. Trist. Pp. 
xv+203+v. (London: Animals’ Guardian 
Office, 1913.) Cloth, 3s. 6d.; paper, Is. 
Apart from the main title, which is much more 
suitable for a novel, and utterly fails to convey the 
faintest inkling as to the nature of its subject, the 
editor and authors of this volume are to be con- 
EEE 
