OcTOIiKR 29, 1896] 



NA rURE 



621 



LETTERS TO THE EDITOR. 



{The Editor does not hold himself responsible for opinions ex- 

 picssed by his correspondents. Neither can he undertake 

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

 manuscripts intended for this or any other part of NATURE. 

 Ao notice is taken of anonymous communications.^ 



Measurements of Crabs. 



On luiie n last, a paper by Mr. Herbert Thomson was 

 communicaleil to the Royal Society, "On certain chanjjes ob- 

 served in the dimensions of parts of the carapace of Carcinus 

 mcenas" (Proc. Roy. Soc, Ix. No. 361). .\ccording to measure- 

 ments recorded in this paper, the male crabs taken at Plymouth 

 in the year 1S95 were narrower in the frontal breadth, and 

 longer in the right denlary margin than male crabs of the same 

 size taken in 1S93. 



The author of the paper states that further measurenients will 

 be necessary in order to decide whether these results indicate a 

 permanent change in the species at Plymouth, or a mere 

 oscillation, such as may be constantly going on in the relative 

 dimensions of parts in a species. 



I venture to remark that species must be much more unstable 

 than we have ever supposed hitherto, if either permanent changes 

 or mere oscillations in their characters are to be detected in one 

 locality in the course of a couple of years. There is one other 

 possible e.xplanation of the observed differences which has 

 occurred to my mind, and is, I think, worth consideration on 

 the part of those who are studying evolution by means of the 

 micrometer. It appears from the paper that the measurements 

 of the 1S93 crabs and of the 1S95 crabs were made, not in those 

 years respectively, but both sets alike after the summer of 1895. 

 The two sets of crabs were, in this case, not measured under 

 identical conditions. If the 1893 set had been longer in spirit 

 than those of 1S95, perhaps this was the reason of the difference. 

 Or there may have been some difierence in the mode of pre- 

 servation. At any rate, I think the comparison is not trustworthy 

 unle.ss the measurements had been made on fresh crabs imme- 

 diately after they were collected — one set in 1893, the other set 

 in 1895. It is doubtful whether mesisurements of spirit speci- 

 mens are ever perfectly trustworthy as representing the true 

 dimensions of animals. 



The fact that a deficiency in one dimension was "com- 

 pen.sated,'' as the author himself expresses it, by an excess in 

 the other, >uggests the question whether the specimen of one 

 lot or the other had not undergone an artificial change of shape. 

 It seems to me that that question must be disposed of before 

 we admit that a permanent or temporary change in the specific 

 dimensions of parts in the crab has been demonstrated. 



J. T. ClN-NI-NGH.\M. 



Some Effects of the X-Rays on the Hands. 



At the request of the editor of Natire, I apjiend the follow- 

 ing description, compiled from notes, of the effect of repeated 

 exposure of the hands to the X-rays. The result, though 

 perhaps interesting from a medical and scientific point of view, 

 has been inost unpleasant and inconvenient to myself — the 

 patient — and although my theories may be incorrect, and my 

 conclusions easy to demolish, there is no mistaking the fact that 

 the X-rays are quite capable of inflicting such injury upon the 

 hands as to render them almost useless for a time, and to leave 

 in doubt their ultimate condition when entirely freed from 

 frequent daily exposure to their influence. 



Now for facts. I commenced demonstrating early in May 

 with a c<jil capable of giving an S" spark, and have been 

 engaged in the work for several hours per day until the ]iresent 

 lime. For the first two or three weeks no inconvenience or 

 discomfort were felt, but there shortly appeared on my right- 

 hand fingers numerous little blisters of a dark colour under 

 the skin. These gradually became very irritating, the skin 

 itself very red and apparently much inflamed. The irritation 

 increased, and the application of aqna-plumbi, as recommended 

 in a Berlin telegram to the Standard, had only a passing effect 

 in allaying it. So badly did my hand smart, that I was con- 

 -stantly obliged to bathe it in the coldest water I could get, and 

 I really lielieve I should have been obliged to resign my appoint- 

 ment had not a well-known medical man, who happened to 

 attend one of the demonstrations, advised me to use a much- 

 advertised ointment. I did so, with the remarkable result that 

 the irritati'in left me immediately, and by using it regularly since 



NO. 1409, VOL. 54] 



then, I have at least avoided one of the disagreeable con- 

 sequences of too much X-rays. In the meantime, however, the 

 skin on the fingers had become very dry and hard, yellow like 

 parchment, and quite insensible to touch, and I was not at all 

 surprised to find, a day or two afterwards, that it began to peel 

 off. When this particularly unpleasant operation had been 

 accomplished, I considered I was quite acclimatised to the rays, 

 but soon found out my mistake. The same symptoms again 

 appeared, the newly-formed .skin going the same way as in the 

 former case. But there was a further discomfort to follow. 

 About the middle of July the tips of my fingers began to swell 

 consideraljly, and appeared as if they would burst. The tension 

 of the skin was very great, and, to crown all, I noticed for the 

 first lime that my nails were beginning to be affected. This 

 was the commencement of a long period of really serious dis- 

 comfort and pain, which was only partly relieved when, from 

 under the nails, there appeared a somewhat copious and un- 

 pleasant-smelling colourless discharge, which continued more or 

 less until the old nails were thrown off. With this discharge 

 the swelling in the finger-tips decreased, but as the new and old 

 nails began to separate in the middle, the pain was renewed, 

 and I was unable to bear the slightest pressure upon them. The 

 old nails turned quite black and very hard, and the state of my 

 hands may be imagined when I say that I had to keej) the 

 fingers in bandages for more than six weeks. It was only in 

 the middle of August that my left hand became affected by the 

 rays, as until then I had principally used my right hand in the 

 manipulation of the fluorescent screen. I naturally expected to 

 again undergo the same experience, with all its discomforts. 

 I had lost the skin of my right hand for the third time, and 

 there seemed to be no probability of that being the last. Several 

 doctors had seen my hands, and taken much interest in their 

 condition, but no one could suggest a remedy. 



M last it occurred to me that all the trouble w-as being caused 

 by the rays burning out the natural oil of the skin, and that if I 

 could in some way supply the deficiency, it might assist in 

 preventing further ill effects. For that purpose I got some 

 lanoline, the oil obtained, so I am informed, from sheep's wool. 

 This I daily rubbed into my hands, and then encased them in a 

 pair of ordinary kid gloves. These gloves, in the course of 

 time, became saturated with the ointment, and there is no doubt 

 that, although in themselves they were quite transparent to the 

 X-rays, and therefore no shield in themselves, the fatty matter 

 did, in a great degree, prevent the drying up of the skin in the 

 manner I have described. I do not mean to .say that it is an 

 absolute preventive, but it goes a long way towards that desirable 

 end, because since I first used the lanoline, now some weeks 

 since, my hands have not again peeled, although at the present 

 moment (October 17) there are a few slight .symptoms of it. 



My view of the effect of the X-rays is that, in regard to this 

 matter, it is exactly similar to acute sunburn. The symptoms 

 and effect are the same, only that, in the case of the X-rays, you 

 have it in a far more concentrated form — in fact the very essence 

 of it. But whatever may be the cause, the effect is unquestion- 

 able. In my case I have had three new sets of skin on the 

 right hand, and one on the left ; four of my finger-nails have 

 disappeared on the right, two on the left, and three more are 

 on the point of leaving. For at least six weeks I was unable 

 to use my right-hand fingers in any way whatever, and it is only 

 since the nails came off that I have been able to hold a pen. Of 

 course it will be a month or two before my hands resume their 

 natural condition, and if is yet, as I said before, a moot point 

 as to what the end will be. 



I could say much more on this subject, but already I fear I 

 have trespassed too much on the editor's space. I have written 

 this with the object of placing upon record "the strange case of 

 an X-rays operator," in the hope that it may add something to 

 what is known of the new and mysterious power, and lead 

 others, more experienced in scientific and medical knowledge 

 than myself, to devise an effectual preventive against such results 

 as I have described. Jlany important questions are opened up 

 by this remarkable effect of the rays upon the skin and nails, 

 and it may be that in the near future they may be utilised in 

 cases of skin and other diseases. Who knows ? S. J. R. 



X-Rays .Syndicate, Indian Exhibition, EarPs Court, London. 



Habits of Chameleons. 

 I HAVE just read Mr. Ridsdale's letter about the Chameleon, 

 and write to say that I have one here which has lived in England 

 since May 23, 1891, when it was brought from the Cape by my 



