262 



NATURE 



[November 4, 191 5 



way the e^jposure can therefore be safely made at least 

 ten times longer than is usually possible by the 

 ordinary method in general use and without damaging 

 the superficial tissues. 



It is to be noticed that the chief advantage of this 

 plan lies in the fact that whereas at the apex of the 

 cone swept out by the revolving beam the radiation 

 is operative during the whole exposure, at the skin 

 surface the pencil of rays only impinges upon a smal) 

 area at any moment, always passing slowly on as the 

 tube revolves so as to irradiate a large ring, section 

 bv section, of perhaps one inch in width. 



Some rough experiments already made by the writer 

 with a crude form of tube frame revolved by hand 

 have given promising results. In spite of the fact that 

 the source of radiation in a focus tube is practically 

 a point, all rays being therefore divergent and thefr 

 intensity falling off inversely as the square of the 

 distance; in spite, too, of the absorption of some of 

 the beam's energy as it traverses the tissues, it was 

 found that the time-intensity factor could be made in 

 this way considerably larger at the seat of the disease 

 than at the skin surface. 



The method is already being given a practical trial 

 at the Cancer Hospital, London, and may prove later 

 to be applicable also in treatment by radium. 



C. E. S. Phillips. 



Castle House, Shooters Hill, Woolwich, S.E. 



Australian Photographs. 



Readers of Nature, and especially members of the 

 British Association, may be interested to know that I 

 have received to-day (October 25), too late for incor- 

 poration in the " Overseas Camera in Australia," now 

 being distributed to subscribers on behalf of the funds 

 of the British Red Cross Society and Order of St. 

 John, a remarkably fine series (300 or more) oF photo- 

 graphs of features of general and scientific interest 

 of New South Wales, presented by the Premier of 

 this State through Mr. J. H. Maiden, the director 

 of the Botanic Gardens, Sydney, and taken by the 

 Government printer. The photographs are of interest 

 to botanists, zoologists, foresters, agriculturists, geo- 

 logists, miners, and astronomers. I shall be glad to 

 supplv lists or further particulars to anyone interested. 



13 Palmerston Park, Dublin. T. Johnson. 



Explosive Bombs. 



I HAVE been studying the effects of explosive bombs 

 on windows, and should greatlj' appreciate any in- 

 formation as to the effect of the explosions on the 

 diagrams of recording barometers : (a) in the open 

 air, (b) in rooms. Alfred S. E. Ackermann. 



25 Victoria Street, Westminster, 



London, S.W., October 28. 



TRENCH "FROST-BITE/' 



DURING the winter campaign of 1914— 15 a 

 number of soldiers fig-hting- in the trenches 

 in Flanders became disabled from the effects of 

 cold and wet on their feet. The condition is to 

 be distinguished from true frost-bite, in which 

 severe cold causes necrosis or death of the tissues ; 

 but though this may occur, it is infrequent in 

 trench frost-bite, the characteristic symptoms of 

 which are swelling, pain, and disturbance of sen- 

 sation in the part affected. For this reason 

 Delepine^ suggests the name "frigorism" or 



J "On the Prevention of ' Frost-Rite' and other Effects of Cold." Joiirti^ 

 Roy. Ar?ny Med. Corps, May, 1915. 



NO. 2401, VOL. 96] 



" frigidism " for this condition, corresponding 

 With "froidure," used by several French writers. 



Three factors seem to be concerned in the 

 causation of trench frost-bite, viz., cold, wet, and 

 interference with the circulation in the leg and 

 foot by tight puttees and boots. Lorrain-Smith, 

 Ritchie, and Dawson 2 have investigated experi- 

 mentally the pathology of the condition. The 

 microscopic examination of the tissues showed 

 that the chief effect of the cold is exerted on the 

 blood-vessels, which become dilated and contain 

 a certain amount of -fibrin deposit, their internal 

 endothelial lining becomes swollen, and the 

 muscle fibres of the middle coat are vacuolated. 

 The axis-cylinders of the nerves of the part be- 

 come swollen and oedematous, and some slight 

 changes in the fibres of the voluntary muscles 

 may be observed. 



Delepine {loc. cit.) has conducted a number of 

 experiments on the causation and prevention of 

 trench frost-bite. He finds that exposure to cold, 

 dry air caused a lowering of temperature of the 

 part, which, however, is slight and not progres- 

 sive, but immersion in a limited amount of cold 

 water caused a rapid and considerable, though 

 not permanent, lowering of temperature, and, pro- 

 vided the bulk of water does not exceed twice that 

 of the part immersed, is not detrimental. When, 

 however, the amount of water at a temperature 

 below that of the skin is unlimited, or if the water 

 is limited in amount but contains ice, the lower- 

 ing of temperature of the part is rapid, consider- 

 able, and progressive, and invariably results in 

 local frigorism, and motion of the external w^ater 

 accelerates loss of heat by preventing the forma- 

 tion of a comparatively warm surface layer. The 

 presence of a thick woollen covering retards loss 

 of heat, even when saturated with water, owing 

 to the warming of the comparatively still layer 

 of water retained within the meshes of the fabric. 

 It was found that a very thin layer of moderately 

 dry air between the skin and the external cold 

 water or ice suffices to reduce the loss of heat to 

 an extent which is compensated by the heat 

 brought to the part by the circulating blood. Such 

 an air layer over the part can be secured by the 

 use of a thin waterproof covering in combination 

 with a woollen covering. 



After many trials. Dr. Delepine has succeeded 

 in preparing very thin and soft oil-silk, which can 

 be made into absolutely waterproof bags for 

 covering any part of the body by means of apposi- 

 tion seams. They are light, inexpensive, and 

 wear well, should be worn over an inner woollen 

 sock, and be protected by an outside sock. With 

 such a combination it is possible for the men to 

 use the boots they have at present, provided they 

 are two sizes larger than ordinarily worn. The 

 oil-silk bags should extend up to the knee, and 

 could probably be made for less than 35. a pair. 

 The importance of having nothing tight round 

 the leg is obvious — the circulation in the part 

 should be as free as possible, so that the cir- 

 culating blood may maintain the warmth of the 

 limb. R. T. Hewlett. 



Lancet, September ii, 1915, p. 595. 



