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POPULAR SCIENCE REVIEW. 
mentioned that M. Van Tieghem alleges that this fibrous layer contracts 
under atmospheric influences upon the chamber, and thus expels the pollen 
grains. He thinks that drought or desiccation causes, or may cause, con- 
traction of the fibres ; but when he considers M. Duchartre’s observations, 
he thinks that even this explanation is unsatisfactory. 
The Synonymy and Distribution of Jussicea repens. — M. de Martins con- 
siders that the supposed numerous species of this plant are really referable 
to one species, which, owing to its extensive distribution, becomes modified 
to a great extent. That these modifications are not hypothetical he has 
proved by submitting the plant to various conditions of soil, temperature, 
water, etc. Subsequently to his experiments he applied to several European 
botanists for specimens of J. repens , and from an examination of them he 
concludes that the species described by Linnseus in 1747 as J". repens has 
received the following twelve names : — adscendens , diffusa, grandijtora, 
peploides, polygonoides, jluvialis, ramulosa, sivartziana, stolonifera, alterni- 
folia , A ustralatica, and fluitans. He gives the following as its distribution. 
It is found in Asia, Africa, America, and Australia. In Africa, from 
Algiers to the Cape of Good Hope, and from Senegal to the Isles of 
Mauritius and Reunion. In Asia, from Syria to India and Ceylon. In 
America the extreme points are Kentucky and the Rio de la Plata, Mexico 
and Bahia. 
Euphorbia palustris in Sussex. — The Rev. Thomas Hutchinson writes to 
inform us that this plant was really discovered by Mr. James Edwards, who 
found it in Blackbrook Wood, Ditchley. The wood has lately been cut down, 
so that specimens cannot be found, but Mr. Edwards hopes next year to find 
the plant as plentiful as ever. 
CHEMISTRY. 
The Sources of Fat in the Animal Body. — On this subject a paper was 
read by Mr. Lawes and Dr. Gilbert before the late meeting of the British 
Association. Some time since, Baron Liebig asserted, that the fat of herbi- 
vorous animals was in great part derived from the hydro-carbon of their food, 
but might also be produced by the nitrogenous substances. This theory was 
opposed by Dumas and Boussingault, who afterwards in part supported it ; 
but at the Congress of Agricultural Chemists, held last year at Munich, M. 
Voit denied this conclusion, and asserted that the fat of herbivora is derived 
from the nitrogenous elements of the food. Messrs. Lawes and Gilbert 
having taken the subject up, have arrived at the following conclusions : — 
(1) That a large proportion of the fat of herbivora fattened for human food 
must be derived from other substances than the fat in their food ; (2) That 
when fed on the most appropriate fattening food, much of the stored-up fat 
must be produced from the carbo-hydrates ; (3) That the nitrogenous con- 
stituents may also serve as a source of fat, more especially in defect of a liberal 
supply of the non-nitrogenous elements. 
What is an Ozonogene ? — It is the name given to an instrument like that 
employed to disengage hydrogen continuously, but in which nitric oxide is 
generated by the action of nitric acid in copper turnings. A little of the 
