28 
of defence—boxing and wrestling. What are 
called balance movements in the Swedish system, 
as well as abdominal movements, are included 
in a truly “utilitarian” manner in climbing exer- 
cises. So far as abdominal movements are con- 
cerned, this does not allow graduation of resist- 
ance, which is a matter of importance. There is 
little variety of limb exercises, and the group of 
back exercises, so valuable for their corrective 
effect in regard to the faulty positions assumed 
in most occupations, are entirely omitted. Head 
and neck exercises are also omitted, while lateral 
trunk movements are only used as applied move- 
ments, and are therefore not graduated. 
The more definite grouping of movements in 
the Swedish system allows of a more graduated 
and equal training for each part of the muscular 
system, each group of muscles, and, therefore, of 
the body as a whole. Free trunk movements, 
lateral and otherwise, are obviously of value in 
acquiring strength, flexibility, ard complete 
coordination. Free arm movements are of 
greater value for the normal development of the 
arms and chest than movements of lifting and 
throwing. 
In a Swedish gymnastic lesson the hardest work 
is performed in the middle of the lesson, the 
amount of exertion being graduated throughout. 
M. Hébert also graduates the amount of work, 
but leaves the hardest work to be performed to- 
wards the end of the lesson. The effect of the 
former method on circulation and respiration, and 
on the distribution of blood in the body, is more 
desirable physiologically. 
M. Hébert lays due stress on the importance 
of deep breathing, and of complete expiration as 
well as inspiration. On the other hand, he recom- 
mends as an exercise slow matching, breathing in 
during four to six steps, breathing out during four 
to six steps, either with or without an intermediate 
respiratory pause with expanded chest for one 
or two steps. This method of breathing would 
undoubtedly tend to produce over-expansion of the 
chest, with loss of elasticity and accompanying 
emphysema. Marching with the hands crossed 
behind the back (Fig. 18) also tends to fix the 
chest and hinder complete expiration, besides pro- 
ducing a bad position of the shoulders and often 
hollow back. Sun and air baths and gymnastics 
in the open air are recommended, the body being 
uncovered except for a short pair of drawers, un- 
less the weather is specially inclement, or the sun 
very hot, when a protective covering for the head 
and back of the neck is added. 
The illustrations as a whole are excellent, 
although some of those which illustrate jumping 
appear to show that the height of the jump is 
NO. 2289, VOL. 92] 
NATURE 
[SEPTEMBER II, 1913 
considered more than the correctness of the 
attitude in jumping (Fig. 94). 
The book is arranged clearly, and is much more 
readable than the more severe and “complete” 
gymnastic treatises. Mina L. Dossir. 
OUR BOOKSHELF, 
L’Aviation. By Prof. P. Painlevé, Prof. E. Borel, 
and Ch. Maurain. Sixiéme edition. Pp. viii+ 
298. (Paris: Librairie Felix Alcan, 1913.) Price 
3 francs 50 centimes. 
Written by well-known members of the French 
aeronautical professions, the book provides a 
simple and interesting account of the position of 
aviation at the present time. The text rarely deals 
quantitatively with the problems connected with 
the construction or motion of an aeroplane, cal- 
culations being left to notes at the end of the 
book; the notes occupy about one-third of the 
whole, and refer to investigations many of which 
are the original work of the authors. 
Only a very short historical portion is provided 
as introduction, but it is interesting to find that 
the work of Sir George Cayley, as a pioneer in 
the development of the theory of the aeroplane, is 
prominently referred to. The ‘coming of the 
aeroplane” is dated from the autumn of 1908, 
when the flights of Farman, Delagrange, Blériot, 
and the striking achievements of the Wright 
Brothers began to attract attention; the sub- 
sequent rapid development of aviation and its 
causes are referred to and illustrated by means of 
a record of the best results obtained at successive 
stages. 
A discussion of the flight of birds in winds, on 
the lines of Langley’s “Internal work of the 
Wind,” is used to illustrate the possibility of 
extracting energy from the wind, and so flying 
without the use “of an engine. 
Aeroplanes of various types, made in the period 
1908-10, are illustrated, and the organs described 
in some detail. The use of the elevator and rudder 
in manceuvring is referred to under gliders, but 
stability, longitudinal and lateral, is referred to 
power-driven machines. Lateral stability is sub- 
divided into “stability of gyration,” that is, 
stability of direction relative to the wind and . 
in the limited sense of keeping ~ 
“lateral stability ” 
an even keel. Bryan has shown that the subdivi- 
sion may be misleading as the two are not inde- 
pendent, and should be treated together. 
The book has the advantage of a very complete 
index, which makes reference a simple matter. 
Household Bacteriology: For Students in Domestic 
Science. By Estelle D. Buchanan and Prof. 
R. E. Buchanan. Pp. xv+536. (New York: 
The Macmillan Company; London: Macmillan 
and Co., Ltd., 1913.) Price ros. net. 
“DomESTIC science ” is rightly coming to the fore, 
and in any course of instruction devoted to this 
subject, some amount of bacteriology, or ‘“ micro- 
biology,” as it may preferably be termed, must 
be included. The present volume practically 
covers the ground of such knowledge of micro- 
ee 
