May 4, 1905 J 



NA rURE 



cumstances it is natural that monographers should 

 have expressed diverse opinions as to the limits of the 

 species, and that different characters and parts of 

 the plant should have been taken as a basis for classi- 

 fication. Bentham grouped the species according to 

 the shape and mode of dehiscence of the anthers, 

 and von Mueller followed his lead. Prof. Tate has 

 proposed a svstem based upon the structure of the 

 fruit, whilst of vegetative characters, the cotyledons, 

 leaf-veins, stomata, gums, and timber have all been 

 tested in the hope of finding satisfactory criteria. 

 Mr. Maiden attaches considerable importance to the 

 bark and timber for the guidance of the forester, bul 

 recognises that the anthers and fruit are the best 

 characters for the systematist. 



In the present monograph the object of the author 

 has been to include, with a description of the impor- 

 tant characters, the substance of all recorded observ- 

 ations and investigations w-hich might assist in 

 determining the position and value _ of species or 

 varieties. Synonyms are considered in detail, with 

 the original description of each where it has been 

 proposed as a species, and the range of each species is 

 noted; finally, the author's views are crystallised in a 

 discussion of the affinities of allied species. These 

 views are based not only on the examination of 

 specimens from important herbaria, but also upon 

 much careful study of the growing trees _ in their 

 native localities. Whilst recognising the desire of the 

 author to render the work as comprehensive as pos- 

 sible, it must be said that its practical value would 

 be increased bv a considerable reduction in the amount 

 of material, in the size of print and in the spacing. 

 The five parts issued amount to 145 pages, and con- 

 tain twenty-four plates for eight species, so that the 

 complete work will be bulky and exclusive as to price. 

 It may be suggested that a supplement to this treatise 

 in the shape of a compendium suitable for foresters 

 and students generally would be most useful. 

 Hymenopteren-Studien. By W. A. Schulz. Pp. 147. 



(Leipzig : Engelmann ; London : Williams and Nor- 



gate, 1905.) Price 4s. net. 

 The present work consists of three essays, the first 

 relating to African Hymenoptera (chiefly Vespidse and 

 Fossores), the second describing new genera and 

 species of Trigonalids, and the third discussing 

 Vespidae and .'\pidEe from the .Amazons. The work is 

 chiefly descriptive, and will hardly appeal to any but 

 specialists, who must of course consult it when work- 

 ing at the faunas and groups which are discussed 

 in it. 



LETTERS TO THE EDITOR. 



[The Editor does not hold himself resfionsible for opinions 

 expressed by his correspondents. Neitlier can he undertake 

 to return, or to correspond with the writers of, rejected 

 manuscripts intended for this or any other part of Nature. 

 No notice is taken of anonymous communications.] 



The High-frequency Electrical Treatment. 



The inquest on a lady who died in the Charing Cross 

 Hospital on April 1 1 must be of interest to those who 

 employ the high-frequency electrical treatment. The re- 

 port of the case in the Standard of April 17 is as follows : — 

 " On April 11 she (the deceased) was under treatment, 

 lying on the electrical couch. Suddenly witness observed 

 the perspiration break out on her face, and immediately 

 stopped the current. He watched her for a while, and as 

 she seemed to be in a collapsed state he administered a 

 spoonful of sal volatile. Then he recognised symptoms 

 which pointed to ' a serious state of affairs,' and sent for 

 Dr. Bailey. The lady was removed to another ward and 

 died in the evening. Death was caused by hemorrhage 

 of the brain, following a rupture of an artery. This was 

 not a consequence of the electrical treatment ; she would 



NO. 1853, VOL. 72] 



probably have died just the same if she had been sitting 

 in the waiting-room, instead of on the electrical couch. 

 It was a mere coincidence. Dr. Bailey and Dr. Frey- 

 berger gave evidence supporting this view of the case." 

 The treatment was that of the high-frequency electrical 

 current. 



Now that high-frequency electrical discharges are much 

 employed in medical work, being the newest and most 

 up-to-date method of treatment for many diseases,^ it is 

 somewhat important that even "mere coincidences," such 

 as that cited, should not be overlooked or treated lightly ; 

 it is only by collecting evidence on such points that any 

 real knowledge respecting the action of the treatment can 

 be obtained. Shortly after the experiments of N. lesla 

 on electrical discharges, I carried on many experiments 

 on the subject, and from somewhat painful experience I 

 have learned that one source of trouble may be overlooked 

 by many, since it is a secondary action, so that while 

 the utmost attention may be given to the behaviour of the 

 discharge itself, but little may be given to the action of 

 the air which has been subjected to an electrical discharge. 

 The danger of breathing such air was pointed out by me 

 long ago (N.\TURE, 1896), and by many other workers with 

 electrical discharges since then. Air which had been 

 acted on by the high-frequency discharge, when breathed 

 caused irritation to the throat and lungs, and a feeling of 

 suffocation, in some cases very severe. This is rather to 

 be expected, since ozone and ozonised air act on blood, 

 albumen, and organic substances readily. Profs. Roscoe 

 and Schorlemmer write thus in their treatise on " Chem- 

 istry " p. 243, vol. i. (subject, ozone) :— " Whilst blood is 

 completely decolorised, the albumen being entirely,^ and the 

 other organic matters being nearly all destroyed.") 



The trouble mentioned was removed to a considerable 

 extent by inducing a strong draught of warm air across 

 the chamber where the apparatus was used. I feel that 

 I am taking a great liberty in suggesting anything to the 

 high-frequency specialist, who will give me at once the 

 reason why self-induction is expressed as " a length and 

 why a rapidly varying electromagnetic field causes flashes 

 of ii<^ht to be seen when the head is placed in such a field. 

 I wSuld suggest that in connection with the method of 

 treatment with the high-frequency discharge, all evidence 

 of new phenomena should be collected and _ sifted in a 

 scientific spirit, whether it be for or against it. 



Operators now take every possible precaution to guard 

 themselves against the evil effects of the X-ray, which at 

 first was treated as quite innocuous. iVlay not the high- 

 frequencv discharge in a modified form have a somewhat 

 similar kind of action, and should it not be treated with 

 as much or at least some, caution? 



F. J. Jervis-Smith. 



The Critical Temperature and Pressure of Living 

 Substances. 



It is well known that living substance is in a labile state 

 its constructive or destructive metabolism being determined 

 bv minute changes, sometimes of temperature or pressure, 

 sometimes of other dynamic conditions. But Mr. Geoffrey 

 Martin's suggestion (Nature, April 27, p. 609) that the 

 lability is due to the great number of atoms in the molecules 

 of living substance, or to the complex " carbon compounds 

 present, gives only a partial explanation. 



The decomposition of a chemical compound under raised 

 temperature, diminished pressure, &c., depends not only on 

 the size and complexity of the molecules, but also on the 

 tendency of the atoms to re-arrange themselves^ and form 

 more stable compounds, generally with dissipation of 

 eneray. For instance, the paraffins with large^ molecules 

 are fairly stable, the products of their decomposition being 

 hydrocarbons still. Fatty acids with equally large mole- 

 cules are less stable, for there is a tendency to split ott 

 substances of higher oxidation, leaving a hydrocarbon 

 residue This tendency increases with the increase ot 

 oxv«en in compounds, and so the small molecule of glucose 

 is 'less stable than the large molecule of fatty acid. The 

 presence of nitrogen is often a cause of instability, 

 especially when the nitrogen forms a link between elements 

 (or groups) of opposite polarity ; and the instability is most 

 marked when the nitrogen is combined with oxygen on the 



