Oct. lo, 1889] 



NATURE 



583 



hydrophobia — clue to the preventive treatment — has occurred 

 amongst the 7000 persons who have so far undergone the 

 cure. 



Now let me put before you the answer to the question, Is this 

 treatment a real cure ? For this has been doubted by persons, 

 some of whom will I fear still doubt or profess to doubt, and 

 still abuse Pasteur whatever is said or done ! From all that can 

 be learnt about the matter, it appears pretty certain that about 

 from fifteen to twenty persons out of every hundred bitten by 

 mad dogs or cats, and not treated by Pasteur's method, develop 

 the disease, for I need scarcely add that all other methods of 

 treatment have proved fallacious ; but bites on the face are much 

 more dangerous, the proportion of fatal cases reaching 80 per 

 cent. Now of 2164 persons treated in the Pasteur Institute, 

 from November 1^85 to January 1887, only thirty-two died, 

 showing a mortality of i "4 per cent, instead of fifteen to twenty, 

 and amongst these upwards of 2000 persons, 214 had been bitten 

 on the face, a class of wounds in which, as I have said, when 

 untreated, the mortality is very high ; so that the reduction in 

 the death-rate seems more remarkable, especially when we learn 

 that in all these cases the animal inflicting the wound had been 

 proved to be rabid. The same thing occurs even in a more 

 marked degree in 1887 and 1888. In 1887, 1778 cases were 

 treated, with a mortality of I "3 per cent., whilst last year 1626 

 cases were treated, with a mortality of I"i6 per cent.^ 



Statistics of the antirabic treatment in other countries show 

 similar results, proving beyond a doubt that the death-rate from 

 hydrophobia is greatly reduced. Indeed, it may truly be said 

 that in no case of dangerous disease, treated either by medicine 

 or surgery, is a cure so probable. Moreover, in spite of asser- 

 tions to the contrary, no proof can be given that in any single 

 case did death arise from the treatment itself. And as showing 

 the safety of the inoculation, I may add that all Pasteur's 

 assistants and laboratory workers have undergone the treatment, 

 and no case of hydrophobia has occurred amongst them. 



You are no doubt aware that Pasteur's anti-rabic treatment 

 has been strongly opposed by certain persons, some of whom 

 have not scrupled to descend to personal abuse of a virulent 

 character of tho;e who in any way encoura;4ed or supported 

 Pasteur's views, and all of whom persistently deny that anything 

 good has come or can come from investigations of the kind. 

 Such persons we need neither fear nor hate. Their opposition 

 is as powerless to arrest the march of science as was King 

 Canute's order to stop the rising tide. Only let us rest upon the 

 sure basis of exactly ascertained faC", and we may safely defy 

 alike the vapourings of the sentimentalist and the wrath of the 

 opponent of scientific progress. But opposition of a much 

 fairer character has likewise to be met, and it has with propriety 

 been asked — How comes it that Pasteur is not uniformly 

 successful? Why,, if what you tell us is true, do any deaths 

 at all follow the anti-rabic treatment ? The answer is not far 

 to seek. In the first place, just as it is not every vaccination 

 which protects against small pox, so Pasteur's vaccination against 

 rabies occasionally fails. Then, again, Pasteui's treatment is 

 really a race between a strong and an attenuated viru-:. In ca^es 

 in which the bite occurs near a nei vj-centre, the fatal malady may 

 outstrip the trt a ment in this race between li'e and death. If 

 the weakened virus can act in lime, it means life. If the strong 

 virus acts first, prevention comes too late — it means death. So 

 that the treatment is not doubtful in all cases, but only doubtful 

 in those which are under well-known unfavourable conditions. 

 This, it seems to me, is a compl.'te reply to tho^e who ignorantly 

 fancy that, because Pasteur's treat m ant has not cured every case, 

 it must be unreliable and woithless. 



One word more. I have said that Pasteur is still— as he has 

 always been — a chemist. How does this fit in with the fact that 

 his recent researches seem lo be entirely of a biological character ? 

 This is true. They seem, but they really are not. Let me in a 

 few sentences explain what I mean. You know that yeast pro- 

 duces a peculiar chemical substance — alcohol. How it does so we 

 cannot yet explain, but the fact remains. Gradually, through 

 Pasteur's researches, we are coming to understand that this is not 

 an isolated case, but that the growth of every micro-organism is 

 productive of some special chemical substance, and that the true 

 pathogenic virus — or the poison causing the disease — is not the 

 microbe itself, but the chemical compound which its growth 

 creates. Here once more "to the solid ground of nature trusts 

 the man that builds for aye," and it is only by experiment that 

 these things can be lea'-nt. 

 ' For further details, sje Dr. Ruff.r, Brit. Med. Journ., Sept, 21, 1889. 



Let ire illustrate this by the n.oft recert and perhaps the 

 most striking example we know of. The disease of diphtheria i& 

 accompanied by a peculiar microbe, which, however, only grows 

 outside, as it were, of the body, but death often takes place with 

 frightful rapidity. This takes place not by any action of the 

 microbe itself, but by simple poisoning due to the products of 

 the growing organism, which penetrate into the system, although 

 the microbe does not. This diphtheritic Bacillus can be cultivated, 

 and the chemical poison which it produces can be completely 

 separated by filtration from the microbe itself, just as alcohol can 

 be separated from the yeast granules. If this be done, and ore 

 drop of this pellucid liquid givtn to an animal, that animal dies 

 with all the well-known symptoms of the disease. This, and 

 similar experiments made with the microbes of other diseases, lead 

 to the conclusion that in infectious maladies the cause of death 

 is poisoning by a distinct cheniical compound, the microbe being 

 not only the means of spreading the infection, but also the 

 manufacturer of the poison. But more than this, it has lately 

 been proved that a small dose of these soluble chemical poisons 

 confers immunity. If the poison be administered in such a 

 manner as to avoid speedy poisoning, but so as gradually to 

 accustom the animal to its presence, the creature becomes not 

 only rel'ractory to toxic doses of the poison, but also even to the 

 microbe itself. So that instead of introducing the micro-organism 

 itself into the body, it may now only be necessary to vaccinate with, 

 a chemical substance which in large doses brings about the disease, 

 but in small ones confers immunity from it, reminding one of 

 Hahnemann's dictum of " Similia similibus curanlur." 



Here then we are once more on chemical ground. True, on 

 ground which is full of unexplained wonders, which, however, 

 depend on laws we are at least in part acquainted with, so that 

 we may in good heart undertake their in\esiigation, and Icok 

 forward to the lime when knowledge will lake the place of 

 wonder. 



In conclusion, I feel that seme srrt of apology is needed in 

 thus bringing a lather serious piece of business beforeyou on this 

 occasion. Still I hope for jour forgivtness, as my motive has 

 1 een lo explain lo )ou as clearly as I could the life-work of a 

 chemist who has in my opinion conferred benefits as yet untold 

 and perhaps unexampled on mankind, and I may be allowed to^ 

 close my discourse with the noble words of our hero spoken at 

 the opening of the Pasteur Institute in ihe piesence of the 

 President of the French Republic ; — 



"Two adverse laws seem to me now in contest. One law of 

 blood and death, opening out each day new modes of destruction,^ 

 forces nations to be always ready for the battlefield. The other 

 a law of peace, of work, of safety, whose only study is to deliver 

 man from the calamities which beset him. 



" The one seeks only violent conquests. The other only the 

 relief of humanity. The one places a single life above all 

 victories. The other sacrifices the lives of hundreds of thousands 

 to the ambition of a single individual. The law of which we are 

 the instruments, strives even through the carnage lo cure the 

 bloody wounds caused by this law of war. Treatment by our 

 antiseptic methods may preserve thousands of soldiers. 



" Which of these two laws will prevail over the other? God 

 only knows. But of this we may be sure, that science in obeying 

 this law of humanity will always labour to enlarge the frontiers 

 of life." 



THE PHYSICAL PAPERS AT THE BRITISH 

 ASSOC! A TION. 



pROF. A, W. RUCKER, F.R.S., read a paper on cometic 

 ''• nebula:. Prof. Lockyer has suggested that comtt-like 

 nebulae may be caused by the passage of a very dense swarm 

 through a stream of meteorites, the relative velocity of the two 

 being very considerable. The author has, therefore, attempted 

 to calculate the increase in the number of collisions which takes 

 place in the rear of an attracting mass which passes through a 

 swarm of meteorites so sparsely scattered through space that the 

 main effects of the attraction are produced in a distance which 

 is small compared with the length of the mean free path. As- 

 suming, with Clausius, that the particles have equal velocities- 

 equally distributed in all directions, and which are small com- 

 pared with the relative velocity of approach, the collisions will 

 be most numerous vviihin a cone ihe apex of which is the attract- 

 ing body or nucleus, and which contains the lines which are 

 parallel to the relative velocities of the individual meteorites 



