February i j, 1892 J 



NATURE 



343 



to ideas differing from those involved in the "new theory," 

 which, so far as extracts such as the above go, appears to include 

 nothing whatever of a theoretical nature. 



Even in Prof. Ostwald's letter there are, however, indications 

 that in his book he went beyond the mere statement of the laws 

 of solutions. For example, he says : " In my book the question 

 is this one of facts, and although I have therein made more use 

 of violecular considerations than I should at present hold to be 

 proper, yet I have done so only to jrender more clear the actual 

 relations, and never to prove quantitative laws." 



Now it was solely the "development of the consequences of 

 facts " — this use, which Prof. Ostwald admits to have been exces- 

 sive, of " molecular considerations " — which has generally been, 

 and was by me, styled the " physical theory." The facts them- 

 selves no one can question ; indeed, I took pains to point out in 

 my review that the facts, as given in the book, would alone 

 serve to make it valuable. The theoretical matter, however, 

 called for separate consideration. It alone was, and, so far as 

 I can see, it alone could be, designated the "physical theory." 



In denying the contrast between the so-called chemical and 

 physical theories. Prof. Ostwald declares that he never main- 

 tained " that no interaction takes place between the solvent and 

 the dissolved substance." If such was his opinion when writing 

 his book, it may be asked, Why in all fairness should he have 

 defined solutions as homogeneous mixtures ? "Why did he not 

 state clearly that interactions between solvent and dissolved sub- 

 stance were possible ? It is quite true that, in my review, in- 

 stances were given of chemical expressions used in the book, 

 hut no stress was put upon these by the author as indicating the 

 general occurrence of chemical changes in solutions. They 

 seemed to arise, not because of, but rather in spite of, the author's 

 idea of the nature of solution, and could only be regarded as 

 inconsistencies. The theme of the book was the explanation of 

 the properties even of concentrated solutions by considering the 

 interactions of molecules of the same kind, by treating the dis- 

 solved substance as if it were gasified. If such a method of 

 treatment were described as " physical,"' I think the commonly 

 accepted meaning of the word was in no way impaired. 



Indeed, much of Prof. Ostwald's book can hardly be justi- 

 fied if interactions of a chemical nature are probable in 

 solutions. For instance, several pages are devoted to the 

 use of van der "Waals's equation in dealing with solutions. 

 To anyone familiar with the deduction of this equation, the 

 validity of its application to a solution even when the solvent 

 is regarded as indiff"erent is highly questionable. If, however, 

 it is admitted that something of the nature of a chemical re- 

 action may occur between solvent and dissolved substance, that 

 the latter may not be in a pseudo-gaseous condition, then the 

 application of the equation can hardly be termed otherwise than 

 meaningless. 



In conclusion, I can only express regret if my review has 

 tended to create further misconception on this vexed question of 

 solution. At the same time, I hope I have been able to indicate 

 to Prof. Ostwald the points which led to my use of the terms to 

 which he objects ; and I venture to think that in the discrepancies 

 which appear to exist between the ideas as given in his letter, 

 and those which the reader has to gather from his book, is to 

 be found sufficient reason for the use of the statements to which 

 exception has been taken. J. W. Rodger. 



London, I^ebruary i. 



Arrow Poison. 



In 1889 a French naval surgeon, M. Ledantec, published 

 in the Annales de C lustitut Pasteur the result of some investi- 

 gations he had made into the nature of the arrow poison of the 

 natives of the New Hebrides. Wounds from these arrows give 

 rise, as is well known, to tetanus, and M. Ledantec was able, 

 by the subcutaneous injection of the scraped oflf poison, to kill 

 guinea-pigs under typical tetanic symptoms. He learnt from a 

 Kanaka that they are prepared by smearing the arrow-heads 

 (which are made of human bone) first with tree gum and then 

 with mud from a swamp, which mud he found to contain 

 numbers of Nicolaier's tetanus bacillus. 



As far as I am aware, this has been recorded only of the 

 natives of the New Hebrides and some of the neighbouring 

 groups (the arrow poison of Stanley's dwarfs is certainly not the 

 .same), and I was therefore much interested some days ago by 

 coming accidentally upon an old record which seems to show 

 that the natives of the Cape "Verd coast were accustomed, more 

 than three hundred years ago, to get rid of their enemies in a 



similar manner. In Hakluyt's ""Voyager's Tales," published 

 in 1589 (I refer to the little reprint edited in 1889 by Henry 

 Morley), is the narrative of one Miles Phillips, in which occurs 

 the following passage : — " Upon the l8th day of the same month 

 (November 1567) we came to an anchor upon the coast of Africa 

 at Cape "Verde, in twelve fathoms of water, and here our General 

 landed certain of our men, to the number of 160 or thereabouts, 

 seeking to take some negroes. And they, going up into the 

 country for the !^pace of six miles, were encountered with a great 

 number of negroes, who with their envenomed arrows did hurt 

 a great number of our men, so that they were enforced to retire 

 to the ships, in which contest they recovered but a few negroes ; 

 and of these our men which were hurt with their envenomed 

 arrows, there died to the number of seven or eight in a very 

 strange manner, with their mouths shut, so that we were forced 

 to put sticks and other things into their mouths to keep them 

 open." In the language of modern medicine, they succumbed 

 to tetanus traumaticus. The voyagers left the coast soon after, 

 and there is no further mention of the natives or of the 

 wounded. 



There is, of course, iio proof that the arrows were poisoned 

 with mud or earth, but the probability is considerable. The 

 chief interest lies in the age of the record, which forms in some 

 manner a pendent to the researches of M. Bossano {Comptes 

 rendus, 1888), which showed the tetanus bacillus to have a very 

 wide distribution in space. 



It is a curious consideration that this and the other famous 

 arrow poison, curare, both kill by their action on the voluntary 

 muscles, the action of one being diametrically opposed to that 

 of the other. A. Coppen Jones. 



Davos Platz, Switzerland, January 30. 



The Implications of Science. 



Hitherto prevented from again writing, I cannot now 

 remain passive and allow Mr. Dixon to escape from bis irra- 

 tional position under cover of a cloud of verbiage — like a 

 cuttle-fish through water made turbid by its ink. 



In my lecture I pointed out that certain truths are implied in 

 all physical science. They are so implied. If Mr. Dixon 

 thinks they are not, it is for him to show how experimental 

 science could be carried on, with any real, serious doubt about 

 them. This he has certainly not yet done. 



Our knowledge of our own existence "in the present," is 

 knowledge of a particular concrete fact, not of an abstract 

 necessary truth. That "whatever feels, simultaneously exists," 

 is such a " necessary truth," but it is an abuse of language to 

 apply that term to anything which may cease to exist the 

 moment after its existence is recognized. 



That " nothing can simultaneously be existent and non- 

 existent," does not at all depend upon "terms" or "defini- 

 tions," but is a law of " things." It would not lose its validity 

 and objective truth, not only if there were no such things as 

 " terms" and "definitions" ; it would not lose it if the whole 

 human race came to an end. 



I am glad to find my critic does " not doubt" that if he lost 

 an eye his condition would thereby be modified, but if he does 

 not also see that this applies and must apply everywhere and 

 everywhen, 1 do not envy him his power of mental vision. 



Oriental Club, February 2. St. George Mivart. 



NO. II 63, VOL. 45] 



The New Fbrest in Danger. 

 In connection with my letter which appeared in Nature of 

 the 28th ult. (p. 295), it may interest some of your readers to 

 know that the petitions, to which I referred, in support of the Bill 

 for excepting the New Forest from the operation of the Ranges 

 Act, 1 89 1, have already been signed by Lord Walsingham, F.R.S. 

 Prof C. Stewart (President of the Linnean Society), Sir Joseph 

 D. Hooker, F.R.S., Dr. P. L. Sclater, F.R.S., Mr. Osbert 

 Salvin, F.R.S., Dr. A. Giinther, F.R.S., Dr. H. Woodward, 

 F.R.S., Mr. W. Carruthers, F.R.S., Dr. D. Sharp, F.R.S., 

 Mr. Thiselton-Dver, C.M.G., F.R.S., Mr. H. W. Bates, 

 F.R.S., Mr. F. DuCane-Godman, F.R.S., Dr. G. Buchanan, 

 F.R.S., Dr. B. Richardson, F.R.S., Prof. J. O. Westwcod 

 (Professor of Zoology, Oxford), Dr. Thome-Thome, F.R.S., 

 Mr. J. G. Baker, F.R.S., Mr. W. H. Preece, F.R.S., Mr. 

 Botting Hemsley, F.R.S.,Mr. E. B. Poulton, F.R.S., Mr. R. 

 McLachlan, F.R.S.,Mr. C. B. Clarke, F.R.S., Major-General 

 Garden, Prof. Jeffrey Bell (Secretary of the Microscopical 



