NATURE 
[| Dec. 29, 1 881 
inclination towards suicide we shall speak in the following 
section ; and then the true professionals, tradespeople, and 
all those reckoned in the vagrant professions.” The sta- 
tistics with regard to the military are remarkable. Thus 
in Prussia the average suicide over the whole male popu- 
lation is 394 per million, while in the army it rises to 600 
or 620. In Austria the proportion is still higher, viz. 866 
per million as against 122 of the civil population, and in 
* the Belgian army the case is nearly as bad. In the 
English army from 1862-71 the suicidal tendency was more 
than triple that of the male civilian population, ‘‘ This 
tendency, moreover, augmented as time advanced ; from 
1862-71 it grew from 278 per million to 4oo, and even 
reached 569 in 1869. The tendency increases with the 
sending away the troops from Europe, so that in the king- 
dom (at home) the number is 339 per million, but in the 
English possessions in India it rises to 468.” Of the dif- 
ferent sections of the British army members of the cavalry 
are most addicted to suicide (in one year the percentage 
among the dragoons being as high as 785 per million), 
next the artillery, then the infantry, foot-guards, engineers, 
and lastly the household cavalry. 
Analysis of the motives which lead to suicide shows this 
as a general result :—“In man the manifestation of per- 
sonal interest rules in [almost] every case, and as only a 
fourth or fifth of the suicides are committed by women, 
the already small proportion of those which are due 
to noble and generous motives becomes still more 
attenuated.” 
Concerning the methods and places chosen by suicides, 
“ Each country certainly has its peculiar predilections, 
but in the aggregate of the peoples by whom suicide is 
practised, the rope appears to be chosen before every other 
instrument, and immediately after that water (both giving 
5-10ths to 8-1oths of cases); firearms follow; then those 
arms which cut or stab; falling from a height is preferred 
to charcoal and poison; and lastly come all the other 
means.” 
Hanging stands in inverse ratio to drowning. For in 
Italy and other countries where hanging is most rarely 
resorted to, drowning is most common, while in Russia, 
where hanging is the favourite mode (four-fifths of all the 
suicides) drowning is very rare (hardly 6’9 per cent.). 
Firearms are preferred in the South of Europe and by 
the military everywhere, while in England poison and 
throatcutting are most favoured. It is curious that 
‘there is a constant difference between the sexes in falls 
from heights and crushing under railway trains, the 
former being proportionally more frequent among women, 
the latter, on the contrary, much more so amongst men.” 
There are other “ sexual divergences” of the same kind, 
and as showing the combined influence of sex and age 
we may quote one other passage :— 
“Males under 15 years of age choose hanging (86 per 
cent.), and women choose drowning (71 per cent.); in the 
ages between 15 and 20 the same predilection of the two 
sexes continues, but it lessens (hanging amongst males is 
72 per cent. ; drowning among women 65), and it grows 
still less between the ages of 20 and 30. With the dimi- 
nution of the tendency towards hanging, that towards 
drowning increases amongst the men, the greatest number 
of deaths by this means falling between the ages of 40 
and 50; but in advanced age the old people return to a 
preference for hanging, even more than children (91 per 
cent.).” 
The book concludes with a short “Synthesis,’? which 
leads to the proposition that “Suicide is an effect of the 
struggle for existence and of human selection [z.e. natural 
selection operating in the human species], which works 
according to the laws of evolution among civilised people.” 
From the present sketch it will be seen that the work as 
a whole contains many facts of interest to sociologists, 
although to the rest of the world its somewhat repulsive 
details will appear useful only as showing the practically 
emphatic answer which sundry classes of the community 
respectively give to the question “ Is life worth living?” 
GEORGE J. ROMANES 
OUR BOOK SHELF 
Catalogue of the Phenogamous and Vascular Cryptoga- 
mous Plants of Michigan—Indigenous, Naturalised- 
and Adventive. By Chas. F. Wheeler and Erwin F, 
Smith. (Lansing: George and Co., 1881.) 
THIS excellent contribution to the flora of the United 
States has been compiled at the suggestion of the 
State Horticultural Society of Michigan. It is prefaced 
with a list of the various catalogues, from that by 
Dr. Jno. Wright, embracing 850 species, and published 
in 1839, to that of Dr. Palmer in 1877. With refer- 
ence to its flora the Peninsula may be roughly divided 
into two great divisions—the hard wood and the soft 
wood-lands—one representing the Appalachian flora, the 
other the Canadian. The hard-wood country lies south of 
latitude 43°, and consists of very fertile sand, clay, or 
loam, mostly cleared of the original forest and largely 
cultivated. The upper Peninsula has a much colder cli- 
mate than that of the lower Peninsula, and its flora isin 
many respects decidedly northern. Pines, fir, cedar, larch, 
elms, poplars, maples, and birch,are among the principal 
trees; the proximity of the great lakes exerts a marked influ- 
ence on equalising the temperature, and the effects thereof 
are wellseen. Trees like Liviodendron tulipifera, Cercis 
canadensis, Gleditschia triacanthos, Cornus florida, and 
Morus rubra, which belong to Ohio and Central Illinois, 
have crept northward, favoured by the mild influence of 
the lake winds through the central and western part of 
the Lower Peninsula often beyond the middle. The flora 
as detailed shows 1634 species. The composites claim 
the larger number of species—iS2—about one-ninth of 
all. Sedges follow with 176 species; Grasses, 139; 
Rosacew, 61; Leguminose, 55; Scrophulariacez, 46; 
Umbellifer, 27. Of the 165 species of trees and shrubs 
about twenty are valuable for their timber. About twenty 
species of woody and herbaceous native climbers are 
frequent, and some seem worthy of cultivation. The 
arrangement followed is that of the fifth edition~ of 
“Gray’s Manual,’’ and a coloured map of Michigan is 
annexed. 
LETTERS TO THE EDITOR 
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Pendulum Observations in London 
THE reference by the President of the Royal Society in his 
recent annual address to the subject of ‘contemplated pendulum 
operations permits me to assume that enough interest exists in 
those operations to render the offer which I now wish, with your 
kind assistance, to make, not altogether inopportune. Iam now 
engaged in swinging pendulums, #7 London, under conditions 
