444 



NATURE 



{Sept. 20, 1877 



South Africa, Cuba, and various parts of North and South 

 America. It has already been stated that it is not hardy 

 in this country, a temperature below the freezing point — 

 or even in some cases a little above it — appearing to kill 

 it. Another useful quality of the tree is that, in conse- 

 quence of its deciduous bark, it is not attacked by para- 

 sites. Baron von Mueller, the director of the IJotanic 

 Gardens at Melbourne, states that the ashes of the wood 

 of this and of other species of Eucalyptus contain a very 

 large proportion of potash, in some cases as much as 

 twenty-one per cent. 



The medicinal properties of the Eucalyptus globulus 

 are due to the presence, so common in trees and shrubs 

 belon<.nng to the Myrtace.t, of a volatile oil, in various 

 parts of the plant, but especially in the mature leaves. 

 This oil may readily be obtained by distillation with 

 ■water, is of a yellow colour when freshly distilled, and 

 resinifies by exposure to the air. Its principal constituent 

 ■was found by C'oez to be a colourless liquid boiling at 

 347° F,, which he regarded as analogous to camphor, and 

 to which he gave the name Eucalyptol ; more recent 

 investigations have shown this to be a mixture of two 

 substance";, a terpene and a cymol, the essential oil con- 

 taining other substances in addition to these. Older 

 statements that the leaves of Eucalyptus contain, besides 

 this essential oil, quinia or some other of the well-known 

 cinchona alkaloids, have been shown, by the researches of 

 Broughton, to be altogether without foundation. 



The value of the leaves as a febrifuge, especially in 

 cases of intermittent fever, has been attested by many 

 medical practitioners, English, Italian, and French ; and 

 in Australia the leaves have long had a popular reputation 

 in the treatment of fevers. They are best administered 

 in the form of an alcoholic tincture, which is also useful 

 as a stimulant and antispasmodic. As an external dressing 

 for wounds it is stated by M. Gimbeit that the balsamic 

 nature of the leaves not only has a curative effect, but 

 removes all the unpleasant odour. The oil is also used 

 as a disinfectant and antisept'c. 



But the point to which the most interest attaches in 

 connection with the Eucalyptus is its alleged anti-malarial 

 properties, in consequence of which it has been called the 

 "fever-destroying tree." On this subject Prof Bentley 

 says that " the evidence that has been adduced from 

 Australia, the native country of the tree, and from all 

 parts of the world where it has been introduced, and 

 which are favourable to its growth, in testmiony of its 

 anti-malarial properties, is so strong that, allowing for 

 exaggeration in some cases, it can scarcely be doubted 

 that this tree does produce a most beneficial effect by 

 destroying the fever-producing miasm of marshy districts : 

 and that it should consequently be introduced into all 

 countries and districts where the climatic influences are 

 favourable for its development, and where such miasmatic 

 emanations are to be found." Special interest attaches 

 to the introduction of the blue gum tree into Italy for this 

 purpose, and it is confidently hoped that by its means the 

 problem may at length be solved of destroying the 

 noxious malaria which has in recent times rendered the 

 level country round Rome so unhealthy in the summer 

 season. The chief difficulty is with the occasional frosts 

 to which Northern Italy is subject. Of a large number of 

 trees planted at one time by the Roman Railway 

 Company along the line from Rome to Naples, only 

 those in the neighbourhood of Naples survived the first 

 winter. It is possible, however, that if they became 

 established through a succession of mild winters, and 

 attained a good size, they might then be able to resist 

 slight fros's. 



The mode in which the trees thus act in influencing the 

 climate is open to somewhat more controversy. The 

 popular idea is that the efficient cause is the odorous and 

 antiseptic emanations from the leaves. It is quite likely 

 that some influence is exerted in this way, but it seems 



most probable that the chief effect produced is by the 

 action of the roots on the soil. This function of trees is 

 often greatly overlooked. The effect of the planting of 

 forests in decreasing the rainfall is frequently erroneously 

 stated to be due to the attractive force of the trees on the 

 moisture in the air, similar to that exerted by a range of 

 mountains ; but it is difficult to conceive that the small 

 mass of the entire foliage of a forest can exert any 

 appreciable influence in this direction. The mode in 

 which trees mainly act is by their roots arresting the 

 rainfall, which would otherwise escape by the natural 

 drainage of the country ; the combined forces of capil- 

 larity, osmose, and transpiration then cause the ascent 

 through the tissues of the tree of the water thus arrested, 

 and the larger portion is eventually given off into the air 

 through the stomata of the leaves. In this way a forest 

 tree w.ll in a very short time give off into the air 

 its own weight in water, which must eventually con- 

 dense, and be again deposited as rain or dew. It 

 is quite possible, however, that the effect of the planting 

 of trees may be apparently the reverse of this in 

 swampy countries where there is no natural drainage. 

 The water then accumulates in the soil ; and, if the 

 country is bare of timber-trees and the sun powerful, a 

 rapid decomposition takes place of the herbaceous vegeta- 

 tion, with the consequent emanation of malarial vapours. 

 The effect of the planting of trees under such conditions 

 will be to supply artificial drainage ; the accumulation of 

 water in the soil and the consequent noxious effluvia will 

 be diminished and finally prevented, and the atmosphere 

 will be rendered, if not drier, at all events more whole- 

 some. This is the mode in which it is hoped that the 

 malarial fevers of the Campagna may ultimately succumb 

 to the influence of the Eucalyptus. In no quarter of the 

 world have the beneficial effects of the planting of this 

 tree been more distinctly seen than in Algeria, where it 

 has been carried on to a considerable extent for some 

 years, mainly through the exertions of private individuals, 

 French and English, aided by the Government. All the 

 good things that have been said about it are there found 

 to have been realised. A. W. B. 



MANTEGAZZA ON THE RELA TIVE LENGTHS 

 OF THE INDEX AND "KING" FINGERS 



THE curious and suggestive researches made about two 

 years ago by Prof. Ecker, of Freiburg University, in 

 the Breisgau, into the comparative lengths of the index 

 and ring fingers, the results of which were embodied in 

 an article contributed to this journal (vol. xiii. p. 8), 

 entitled, " A new Palmistry," have, in the meantime, 

 been further followed out by Prof. Mantegazza, of 

 Florence.^ 



With the aid of another observer the Florentine pro- 

 fessor has made several hundred observations, almost all 

 upon Italians, the subjects being for the most part 

 Romans, Tuscans, and natives of Lombardy. The results 

 are classified in the following table : — 



> "Delia Lunghezza relaliva dell' Indkc e dell' Anulare della Mano 

 umana. Nota del Profes'ore Paolo Mantegazza." Archivio ptr VAntrc- 

 folagiii e la Etttologia, vol. vii. p. 19. Firenzc, 1877. 



