28 NATURE 

[January 6, 1923 
Research Items. 
SuicipE RatEes.—The relation of suicide to climatic 
and racial factors, and to industrialism, occupation, 
urban conditions, age, and sex, etc., is the subject of 
an extensive statistical analysis by Dr. J. R. Miner 
(American Journal of Hygiene, Monographic Series, 
No. 2). It has long been recognised that the suicide 
rate is higher among the Nordic race than among 
Alpine or Mediterranean peoples. Mixed peoples 
usually have a higher rate than either of the pure 
races to which they belong. Foreigners in New York 
show a higher suicide rate than in the countries from 
which they came. The lowest rate is found in Ireland 
and the highest in Saxony, while the rate varies in 
different parts of France according to the racial 
composition of the population. Among Asiatic 
peoples, the Japanese and Chinese rates are high, 
while in India it is low (4:8 per 100,000). India 
appears to be the only country where female suicides 
exceed the male. The general trend of suicide rates 
has been upward during the last century, but the 
higher rates tend to become stabilised. A sharp 
decline took place during the war. Germany, France, 
Denmark and Sweden have high rates, Britain, 
Norway and the Netherlands low rates, as well as 
southern and eastern Europe. In the United States 
the rates are lowest in the south and highest in the 
west. The fundamental causes of these differences 
are found to be probably in (1) differences in the 
strength of the group spirit, (2) adverse economic 
conditions, (3) racial factors, (4) general health of 
the population. 
REPRODUCTION IN THE LrEopicipD#,—Prof. A. L. 
Treadwell’s memoir on the Leodicide (Eunicide) of 
the West Indian Region (Dept. Marine Biol. Carnegie 
Instn., Washington, 131 pp., 9 pls., 467 text figs., 192T) 
gives a full systematic account and records in the 
text and in the coloured plates the character of the 
living coloration’ Included in this family is Leodice 
(Eunice) fucata, which lives in crevices of the coral 
rocks, protruding the anterior end for feeding but 
not exposing the remainder of the body except at 
the breeding season. On the approach of the breed- 
ing season the body becomes much distended with 
eggs or with sperms and swarming occurs usually 
in coincidence with the last quarter of the June-July 
moon. During the night the worms protrude their 
posterior ends from the rocks and break them off 
at the junction between the sexual and non-sexual 
portion. The sexual portion swims to the surface 
and is found in large numbers on the surface at 
daybreak. Just at sunrise the thin body-wall bursts, 
the eggs and sperms are liberated, and fertilisation 
of the eggs occurs. Prof. Treadwell showed in 1914 
that there is a measurable increase in the output of 
carbon dioxide by the egg as it approaches maturity, 
and he suggests that increased elimination of waste 
products into the body cavity of the worm may act 
as a stimulus to egg-laying. 
DIGESTION OF Woop BY THE SHIPWORM. — Dr. 
P. Bartsch’s monograph of the American Ship- 
worms (Bull. 122, U.S. Nat. Mus., t922, 51 pp., 
37 pls.) is restricted to the systematic aspect. He 
recognises in the family Teredide three genera— 
Bankia, divided into four sub-genera, with eight 
species; Bactronophorus, not yet reported in 
American waters; and Teredo, divided into seven 
sub-genera, with twenty-one species. Systematic 
descriptions of and keys to the species are given. 
Dr. Bartsch remarks that although the shipworm 
takes wood resulting from its boring operations into 

secretions of the digestive glamds are capable of 
producing from the wood any soluble carbohydrate. 
Harington (Biochem. Journ. xv., 1921, pp. 736-741) 
investigated this point more than a year ago and, 
though he was not able to reach a definite conclusion, 
the balance of evidence was in favour of the view 
that Teredo has in its liver an enzyme capable of 
producing glucose from some constituent of wood, 
and hence it may be supposed that the wood is to 
some extent made use of as a source of nourishment. 
AMERICAN MycoLtocy.—The first part of volume 9 
of the Annals of the Missouri Botanical Garden 
(February 1922) is completely filled with a revision 
by Prof. E. A. Burt of the North American species 
of Clavaria. This study will be of great value to 
American students of this group of fungi, and British 
mycologists will note with satisfaction that full use 
is made of the valuable study of the British species 
by Cotton and Wakefield in the Transactions of the 
British Mycological Society (1919). The author’s 
discussion shows that plenty of work remains to be 
done by American mycologists, but probably this 
work with its full reference to American type speci- 
mens will provide the necessary stimulus as well as 
the basis from which to start. The illustrations, 
photographs of dried herbarium specimens, seem 
scarcely suitable for a work of this systematic 
character. In some cases, recognition may be 
facilitated by the photograph, in others it may well 
be misleading to unexperienced mycologists. Figures 
90, 91, 92, and 94 might very well have been obtained 
from a single gathering of any one of the four species 
illustrated. 
WET BuLs TEMPERATURES AND THERMODYNAMICS. 
—In the memoirs of the Indian Meteorological 
Department, vol. xxiii. part 1, Dr. C. W. B. Normand, 
Imperial Meteorologist, discusses wet bulb tempera- 
tures and the thermodynamics of the air. In India 
in recent years the daily values and the monthly 
means of wet bulb temperatures have been published, 
since medical officers pay more attention to the wet 
than to the dry bulb readings, especially as to con- 
ditions liable to cause heat strokes. The aim of the 
paper is to create further interest in the actual 
wet bulb temperatures. Mathematical considerations 
are freely introduced, and the discussion opens up 
the subject to wider considerations. At the fort- 
nightly meeting held at the Meteorological Office on 
October 30, the paper by Dr. Normand was taken 
for discussion, and the subject was opened by the 
author, who is now in England. A summary of the 
discussion at the Meteorological Office is given in 
the Meteorological Magazine for November. It was 
brought out that the term “ wet bulb temperature ” 
in the paper is ambiguous, and it was suggested that 
it seems better to use the term “‘ adiabatic saturation 
temperature.” 
METEOROLOGY IN INDIA.—A report on the adminis- 
tration of the Meteorological Department of the 
Government of India in 1921-22 has just been 
received. It is drawn up by Dr. Gilbert T. Walker, 
Director-General of Observatories to the Indian 
Government. After special investigation Stevenson’s 
thermometer screens, commonly used in Great Britain, 
are to replace the large open-sided shade hitherto 
used in India for the exposure of thermometers. 
This will bring India into line with our home observa- 
tions, and will effect a very great saving of expense 
its alimentary canal, it is questionable whether the ' when new screens are required. The English screen 
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