Jtcnc 17, 1880] 



NATURE 



143 



oil of turpentine and substances allied to the terpenes 

 have the property of transforming oxygen into ozone. 

 There is no doubt whatever that ozone is soluble in oil 

 of turpentine ; this is incontestably proved by the experi- 

 ments of Soret, who, as all chemists know, has made 

 capital use of the fact, but this is quite another thing to 

 saying that oil of turpentine generates ozone. This con- 

 fusion between ozone and hydrogen peroxide has mainly 

 arisen from the difficulty of discriminating between the 

 two substances, and it is only since the researches of 

 Struve, made about ten or eleve-i years since, that the 

 presence of the latter body in the air may be said to have 

 been demonstrated. Observers were led astray by the 

 supposition that the simultaneous "existence of the two 

 substances was impossible; chemically speaking, they 

 were held to be incompatible. Recent observations have 

 shown that the opinions hitherto held on this point must 

 be modified. We are at present very much in the dark 

 as to the causes which lead to the formation of peroxide of 

 hydrogen in nature, but that many plants, and especially 

 those which secrete essential oils, contribute to its pro- 

 duction is almost certain. In the book before us Mr. 

 Kingzett has collected a mass of evidence on this matter, 

 and has presented it in an eminently readable and 

 interesting form. Perhaps the most valuable part of the 

 work is that which relates to the power exercised by the 

 various members of the genus Eucalyptus in preventing 

 or destroying malaria — which power according to our 

 author is related to their property of forming peroxide of 

 hydrogen. 



The Eucalyptus globulus was discovered by Labil- 

 lardiere in Tasmania towards the close of the last century, 

 but it is only within the last quarter of a century that its 

 anti-miasmatic properties have become known to Euro- 

 peans. To whom the credit of the discovery is due is not 

 clearly made out. ]\I. Ramel, Baron Miiller, and Sir W. 

 Macarthen appear to have been among the first to draw 

 attention to its extraordinary power, and seeds of the tree 

 were sent by them from time to time to Europe. The 

 testimony in support of this power is most convincing. 

 In marshy districts near Eucalyptus forests fever seems 

 to be unknown, and in parts of Corsica and Algeria 

 where the tree has been planted for the sake of its reputed 

 virtues endemic fevers have been stamped out. M. 

 Gimbert, in a report to the French Academy, instanced 

 the case of a farm situated in a pestilential district about 

 twenty miles from Algiers, where by planting a number 

 of the trees the character of the atmosphere was entirely 

 changed. Similar testimony comes from Holland, the 

 South of France, Italy, California, and many other parts 

 of the world as to the febrifugal attributes of this tree 

 In no case is the evidence more convincing than in that 

 of Algeria, as we have it related to us by Dr. Santra, and, 

 quite recently, by Consul Playfair. Large tracts of land 

 have been quite transformed by the agency of the "fever- 

 destroying tree "as it has come to be called, and wherever 

 it is cultivated fevers are found to decrease in frequency 

 and intensity. Fewer districts in Europe have a more 

 evil reputation than the Campagna as a veritable hot-bed 

 of pestilential fever, and people who know the country 

 round Rome may remember the monastery at Tre 

 Fontane on the spot, as tradition tells, that St. Paul met 

 his death. Life in this monastery meant death to the 



monks, but since the Eucalyptus'has been planted in the 

 cloisters fever has disappeared and the place has become 

 habitable. 



That the aromas of plants have in all ages been held to 

 act as preventives of disease, especially against those of 

 an infectious or malarial type, is well known, and in 

 every visitation of plague which has afflicted this country 

 we read of people carrying strong-smelling gums or 

 balsams about their persons. The physicians of a bygone 

 time had vinaigrettes in the handles of their canes to 

 protect them from the e.xhalations of their patients, and 

 the miserable wretches who came out of the fever-haunted 

 prisons and bridewells of a century or two ago to stand 

 their trials were surrounded by some aromatic herb to 

 protect the court from possiblj contagion. Even the 

 chaplain as he accompanied the doomed man to the 

 gibbet had presented to him a bouquet as a precaution 

 against the dreaded jail-fever. 



Whether peroxide of hydrogen is invariably produced 

 by the process of oxidation of the aromatic parts of 

 plants is not yet proved, but that it frequently is so seems 

 beyond question. There can be no doubt too that this 

 substance is a very powerful antiseptic ; the experiments 

 of Mr. Kingzett and others are quite conclusive on this 

 point. 



OUR BOOK SHELF 



The Science of Voice Production and Voice Prcservatioji, 



for the Use of Speakers and Singers. By Gordon 



Holmes, Physician to the Municipal Throat and Ear 



Infirmary. (London : Chatto and Windus.) 



The author says that this work is an abridgment of 



his " Vocal Physiology and Hygiene," of which a notice 



has already appeared in Nature (vol. xxi. p. 271), and 



that it is intended "to furnish persons who make an 



artistic or professional use of the vocal organs with a concise 



account of those relations of the voice to physical and 



medical science which are only cursorily alluded to, or 



passed over altogether, in treatises on elocution and 



singing." 



The account is concise enough, in the sense of not 

 occupying much space, if we omit the chapter headed 

 " Hygiene of the Voice," which is mainly occupied with 

 general hygiene ; but we greatly doubt whether those who 

 "make an artistic or professional use of the vocal organs" 

 will derive much advantage from its study, that is, whether 

 they will be able to carry away inu:h that will be of use 

 to them. In striving to be concise the author seems to 

 have become vague. Although, of course, he must be 

 professionally well acquainted with the details of the vocal 

 organs and their laryngoscopic appearance, he has not 

 succeeded in conveying a clear knowledge of so much as it 

 imports the singer and public speaker to know. Nor are his 

 woodcuts of the larynx at allsatisfactory ; those, for example, 

 of " the larynx when sounding a note about the level of the 

 ordinary speaking voice," and '•' during the emission of 

 falsetto notes," being calculated to convey false impres- 

 sions to those who see them for the first time. His know- 

 ledge of the physics of sound, and especially of phonetics, 

 appears to be entirely secondhand. There is the same 

 impression conveyed by his treatment of the registers and 

 voice training for singers. The consequence is a want of 

 definiteness and exactness in all these important branches 

 of his subject. Thus, on p. 2, he tells us that sound 

 travels through air at the rate of about 1,090 feet in a 

 second, but neglects to add "at freezing temperature," or 

 that it goes faster when the air is heated, so that, in fact, 

 about 1,120 feet at 60' F. is the more common rate. At 



