March 2, 1916I 



NATURE 



19 



flagellate forms— often Leishmania-like — were more 

 numerous. The authors recall the fact that a flagel- 

 late stage of Leishmania donovani — the causal 

 organism of kala azar in man — has recently been 

 found by Dr. Wenyon in a dog subinoculated with a 

 strain derived from a human case, and that flagellate 

 stages of L. tropica — the organism of oriental sore — 

 have been found in man. In view of the similarity 

 of the morphological cycles of Leishmania and Herpe- 

 tomonas, the authors suggest that the species of 

 Leishmania are probably insect herpetomonads intro- 

 duced long ago into man, and usually perpetuating 

 the non-flagellate and relatively non-resistant forms, 

 though capable of assuming the flagellate forrn. 



THE NEW ZEALAND INSTITUTE. 



'X'HE forty-seventh volume of the Transactions and 

 ^ Proceedings of the New Zealand Institute con- 

 stitutes a record of much valuable and painstaking 

 research, dealing chiefly with the fauna and flora of 

 the Dominion. It is gratifying to find that the war 

 has interfered so little with the activities of New- 

 Zealand naturalists, and that so many ardent workers 

 are now engaged in adding to our already very exten- 

 sive knowledge of this important region. Most of the 

 papers in this volume are of a systematic character, 

 and probably work of this kind is the most important 

 that can be undertaken at the present time in New 

 Zealand. Such papers, however, na^rally appeal to 

 a very limited number of readers, especially when they 

 are written in the ultra-technical language which so 

 many systematists seem to prefer. This appears very 

 markedly in Mr. Meyrick's revision of New Zealand 

 Tineina, in which the diagnosis of the very first genus 

 contains the following cryptic sentence — if sentence 

 it can be called: — " Hindwings under i, termen 

 abruptly emarginate beneath acutely produced apex ; 

 3 and 4 rather approximated, 5 nearly parallel, 6 and 

 - rather approximated towards base." 



We cannot help thinking that, apart altogether 

 from the question of style, a somewhat more generous 

 expenditure of type would be appreciated by those who 

 might like to take up the study of this group of 

 Lepidoptera in New Zealand, and are not already 

 experts in the subject. Mr. Meyrick is of opinion that 

 there still remain a large number of additional species 

 of Tineina to be discovered in New Zealand, and it 

 seems a pity, therefore, that the generic and family 

 characters given only hold good for the New Zealand 

 species, for apparently they may be upset at any time 

 by further discoveries, and may prove quite inadequate 

 for the determination of new forms. 



One of the most interesting discoveries recorded in 

 the volume is that of a new genus of gymnoblastic 

 hydroids, .Ascidioclava, found living as a parasite in 

 the peripharvngeal groove of an Ascidian, and de- 

 scribed by Prof. H. B. Kirk. 

 We are glad to see that local botanists are paying 

 rtention to the life-history of the Lycopodiaceae, which 

 :orm such an important element in the New Zealand 

 flora. Mr. J. E. Holloway contributes a note on the 

 protocorm of Lycopoditim laterale. and Miss K. V. 

 Edgerley describes the prothallia of three species. Prof. 

 Charles Chilton gives an interesting account of the 

 recently established Mountain Biological Station be- 

 longing to the Canterbun,- College, the existence of 

 which may be expected to do much to promote bio- 

 logical research. 



It is impossible in a short notice to do. justice to 



-uch a mass of valuable material as this volume con- 



uns. We can only express our satisfaction at the 



reat activity displayed, and congratulate all con- 



-rned on the results of their labours. A. D. 



NO. 2418, VOL. 97] 



THERAPEUTIC ACTION OF ULTRA- 

 VIOLET RAYS. 



ATTENTION has recently been directed again to the 

 -^*- therapeutic action of ultra-violet rays by the pub- 

 lication of a paper in the Lancet of January S, in which 

 a source of light invented by Mr. Simpson was referred 

 to. There is nothing novel, of course, in the fact that 

 certain forms of disease may be cured by exposure to 

 light of wave-length ranging from 300 ixfi to 90 fifi, 

 but the discovery of a new ultra-violet lamp raises 

 many questions of wide interest. Dr. Sidney Russ has 

 now shown, however, that an arc simply produced 

 between two tungsten rods exactly simulates the so- 

 called ■• Simpson Hght," and it is evident that the 

 powerful source of ultra-violet rays thus obtained will 

 prove of service in the treatment of all those super- 

 ficial lesions which Finsen and others have proved ta 

 be favourably affected by this type of radiation. Dr. 

 Russ has further pointed out that even one-tenth of a 

 millimetre of human skin readily absorbs a large part 

 of the ultra-violet rays from this arc, and that less 

 than one per cent, passes to a depth of one millimetre. 

 When its spectrum is compared with that of the 

 mercury arc, the carbon arc, or one between copper 

 and silver, it is seen to consist of numerous lines 

 grading off towards the shortest wave-length, and 

 affording an exceptionally rich source of ultra-violet 

 light over the region, which is of great therapeutic use. 

 In medical work, however, the cleanliness and con- 

 venience of the method by which any particular radia- 

 tion can be produced are naturally of great importance^ 

 and in this respect it is evident that the electric dis- 

 charge between a broken column of mercury enclosed 

 in an exhausted quartz tube has much to recommend 

 it. On the other hand, the new tungsten arc lamp 

 made by Messrs. Edison and Swan (see Nature of 

 December 23, 1915, p. 467), enclosed in a silica bulb 

 instead of in glass, would no doubt be an ideal means 

 of producing ultra-violet light, and one which could 

 be readily adapted for medical as well as other pur- 

 poses. 



Dr. Russ has contributed a short illustrated article 

 to the British Medical Journal for January 22, 

 in which some interesting points are considered respect- 

 ing the seventeen octaves of radiations which are now- 

 available : from visible Hght to the gamma rays of 

 radium. He deals very clearly with the X-ray spec- 

 trum, the dangers of prolonged or frequent exposure 

 to that radiation, ultra-violet light, and some of the 

 chief physical facts with which medical students should 

 become acquainted. 



T' 



THE UTILISATION OF PEAT.^ 



Peat as a Source of Power. 



HE problem of the utilisation of peat for industrial 

 purposes is one of perpetually recurring interest, 

 and scientific men in many countries have turned their 

 attention to search out a solution. This is not sur- 

 prising in view of the fact that the amount of com- 

 bustible matter in the world's peat deposits exceeds 

 that of all the known coal-fields. For Ireland the 

 question is one of vital interest. Her coal deposits 

 are small and relatively unimportant, while nearly 

 one-seventh of the area of the country-, i.e. more than 

 two and three-quarter million acres. Is covered with 

 peat, much of which is of excellent quality. This 

 represents a vast amount of potential energy awaiting 

 only a practical means of utilising it. 



1 Abridged from articles entitled "Peat as a Source of Power," by Mr. 

 George Fletch-r, and " Some Chemical .A-pccts of the Peat Problem," by 

 Prof. G. T. Morgan, F.R.S., published in the Journal of the Department of 

 Agriculture and Technical Instruction for Ireland (vol. xvi., No. i). 



