246 



NATURE 



[January 12, 1893 



those four earlier sun-spot cycles, at least, we had had, on the 

 whole, wetter years about sun-spot maxima than about the 

 minima. A good deal was written on the subject (as your own 

 columns show) in the seventies ; and the data used seem to have 

 been generally those of annual rainfall. Of late, apparently, the 

 matter has attracted less notice ; for the reason (I suppose) that 

 the correspondence referred to has not been maintained, and 

 recent facts have seemed rather against the theory of a causal 

 relation between the two orders of phenomena. 



Thus the teaching of the curve here given appears to har- 

 monize, in general, with known facts about annual rainfall. I do 

 not propose to try and weigh the data so far as they may be 

 considered to favour the. theory just indicated (earlier and greater 

 part of the curve), nor the data which may be considered 

 adverse (in the short, later part). It seems to me that the curve 

 may be usefully studied per se, apart from any relation to sun- 

 spots. Thus we might note the fact that all those maxima 

 where our summers have got to a turning point from wet to dry 

 have been quite near the beginnings of the decades. The dates 

 are 1830, 1839, 1850, i86i, and 1880. The curve ends at 1890 

 (the final point representing, of course, 1888-92), and the posi- 

 tion of this point, together with the date, seem to warrant our 



Smoothed curve of 1 



days in Summer at Greenwich, with curve of 

 Sun-spols. 



looking for an early descent of the curve, and a commencing 

 series of (on the average) drier summers than we have had 

 lately. 



We might also note that the minima of the curve have ranged 

 from the fives to the eights. Thus we have, 1827, 1835, 1845, 

 1857, 1868, 1885. Should the recurrence continue, we might 

 look for the next minimum about 1895-1898. Of course there 

 may be difference of opinion as to the strength of the presump- 

 tion here afforded for such a forecast, and no good reason is 

 offered (beyond experience) why the curve should now take the 

 course roughly indicated. 



It is not at variance with the above view that there is reason, 

 it would appear, to anticipate soon a series of wetter j/^arj-. In an 

 article contributed to the Times of October 22 last year (cited in 

 Nature, vol. xliv. p. 630) Mr. Symonssays : " There is no doubt 

 that since 1887, at all events, the rainfall over England has 

 been much below the average ; and a consideration of all the 

 facts leads to the conclusion that such a period of scarcity is 

 very likely to be followed by one of abundance, and that the 

 coming few years will probably be more rainy than those re- 

 cently experienced, although possibly the increase will not 

 occur in the summer months— at a time when it would be most 

 noticed." A. B. M. 



'Aminol. 



My attention has only now been called to the letter of Dr. 

 Klein, which appeared in Nature, ante, p. 149. 



To the remarks referring to " Aminol" (with Periodate I am 

 in no way concerned) I desire, with your kind permission, to 

 make the following reply, as they contain inaccuracies which, 

 if not corrected, must do me injury. 



The samples of "Aminol" alluded to by Dr. Klein were 

 sent by me to a number of medical practitioners who had kindly 

 consented to give it a trial. The strength of the samples was 

 I in 5000. 



NO. 12 II, VOL. 47] 



Dr. Klein has carried out between September, 1890, and 

 March, 189 1, five separate consecutive series of experiments 

 with " Aminol," with the object of testing its applicability to- 

 the treatment of certain external disease processes. His re- 

 sults are recorded in a report, the summary and conclusions of 

 which were publi hed last year with his full approval. The 

 strength of solution employed in the first four series (which were 

 only of a tentative nature with a view to arrive at a proper 

 strength of solution for practical application) was i in 6000; in 

 the fifth series a solution of the strength of i in 600 was used. 

 Dr. Klein's letter leads one to suppose that he operated only 

 with the latter strength. 



The pathogenic germs selected for testing the power of the 

 disinfectant were : spores of Bacillus anthracis, sporeless 

 Bacillus anthracis. Staphylococcus aureus. Bacillus diphthericKy 

 and Streptococcus erysipelatis. Amongst the results obtained 

 with the solution of the strength of i in 6000 his report men- 

 tions the following : In Series IV. , "On Staphylococcus aureus, 

 which may be taken as the most resistant microbe amongst 

 those associated with surgical and other external disease pro- 

 cesses, the "Aminol" solution (i in 6000) did produce an 

 effect, though a limited one, after two hours already, and after 

 twenty-four hours destroyed the microbes." In Series I. r 

 " ' Aminol ' solution (l in 6000) kills the Bacillus diphtheria in 

 two hours. This was confirmed in Series III." In this con- 

 nection it deserves to be noted that I possess already ample 

 evidence, which will be published in due course, of conspicuous 

 successes obtained in practice not only with the solution of the 

 strength of i in 5000, but also with dilutions of the same, even 

 to I in 20,000. 



Dr. Klein's statement of the results which he obtained with 

 " Aminol" in the strength of i in 600 is misleading. He says : 

 "Spores of Anthrax bacilli remained unaffected after eight 

 hours, only after an exposure of twenty-four hours did the 

 number of living spores decrease ; but some escaped disinfec- 

 tion even after so long an exposure. Now what are the facts? 

 I quote from Dr. Klein's report : — 



" Spores oi Bacillus anthracis after ) ^ ^ ^^ 



I, 2, 8, and 12 hours \ ^ ^ 



" Spores of Bacillus anthracis after 1 

 24 hours ' 



Is it putting the case fairly or even clearly, seeing that no tests 

 were made between twelve and twenty-four hours, to say 

 " only after twenty-four hours did the number decrease," 

 and seeing that only 6 per cent, remained after twenty-four 

 hours ? Is not that a decrease practically amounting to 

 disinfection ? Would it be extravagant to assume that the in- 

 significant percentage remaining would be eliminated after a 

 very little longer exposure (say another hour), and is there any 

 doubt that a solution of the strength of i in 500 or i in 400 

 would have accomplished complete disinfection in a much shorter 

 time than twenty-four hours ? But in order to illustrate the sig- 

 nificance of the results actually obtained with this solution of the 

 strength of i in 600, let us see which other disinfectants can kili 

 anthrax spores in twenty-four hours. I quote from " Koch on 

 Disinfection," abstracted and translated by Whitelegge, pub- 

 lished by the New Sydenham Society : — 



(1) "For practical purposes a disinfectant should not require 

 much longer than twenty-four hours." 



(2) "Except chlorine, bromine, and iodine, only mercuric 

 chloride, osmic acid, and potassic permanganate (5 per cent.) 

 destroyed anthrax spores within twenty-four hours. Since a 5 per 

 cent, solution of permanganate is inadmissible for disinfection 

 in bulk, and osmic acid is out of the question, we have left only 

 mercuric chlori I e and iodine, bromine, and chlorine." 



The strengths in which the above-named substances succeeded 

 in destroying anthrax spores in twenty-four hours are stated in 

 Koch's tables thus : — 



Permanganate, aqueous solution 5 per cent (i in 20). 



Bromine ,, 2 ,, (i in 50). 



Chlorine ,, ? 



Iodine ,, ? 



Mercuric chloride ,, i per cent (i in loo). 



Osmic acid ,, i ,, (i in 100). 



Now put against this the fact.quoted above, that Dr. Klein found 

 " that ' Aminol,' strength i in 600, killed 94 per cent, of anthrax 

 spores in twenty-four hours," and further (I am quoting his 

 report again), "that this solution is a perfectly harmless fluid as 

 regards the human organism ; therefore no undesirable disturb- 



growth reduced 

 from 100 to 6." 



