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NATURE 



[September 17, 1896 



form the "comma bacillus," and by the French the cholera 

 vibrio. Great doubts were for a long time felt regarding this 

 discovery. Several other kinds of bacteria were found of the 

 same shape, some of them jjtoducing very similar appearances 

 in culture media. But bacteriologists are now universally 

 agreed that, although various other conditions are necessary to 

 the production of an attack of cholera besides the mere presence 

 of the vibrio, yet it is the essential materies morbi ; and it is 

 by the aid of the diagnosis which its presence in any case of 

 true cholera enables the bacteriologist to make, that threatened 

 invasions of this awful disease have of late years been so success- 

 fully repelled from our shores. If bacteriology had done nothing 

 more for us than this, it might well have earned our gratitude. 



I have next to invite your attention to some earlier work of 

 Pasteur. There is a disease known in France under the name 

 of (hoh'ra dcs ponies, which often produced great havoc among 

 the poultry yards of Paris. It had been observed that the 

 blood of birds that had died of this disease was peopled by a 

 multitude of minute bacteria, not very dissimilar in form and 

 size to the microbe of the lactic ferment to which I have before 

 referred. And Pasteur found that, if this bacterium was culti- 

 vated outside the body for a protracted period under certain 

 conditions, it underwent a remarkable diminution of its viru- 

 lence ; so that, if inoculated into a healthy fowl, it no longer 

 caused the death of the bird, as it would have done in its original 

 condition, but produced a milder form of the disease which was 

 not fatal. And this altered character of the microbe, caused by 

 certain conditions, was found to persist in successive generations 

 cultivated in the ordinary way. Thus was discovered the great 

 fact of what Pasteur termed the allJnuation ties virus, which at 

 once gave the clue to understanding what had before been quite 

 mysterious, the difference in virulence of the same disease in 

 different epidemics. 



But he made the further very important observation that a 

 bird which had gone through the mild form of the complaint, 

 had acquired immunity against it in its most virulent condition. 

 Pasteur afterwards succeeded in obtaining mitigated varieties of 

 microbes for some other diseases ; and he applied with great 

 .success the principle which he had discovered in fowl-cholera 

 for protecting the larger domestic animals against the plague of 

 anthrax. The preparations used for .such preventive inoculations 

 he termed " vaccins," in honour of our great countryman, 

 Edward Jenner. For Pasteur at once saw the analogy between 

 the immunity to fowl-cholera produced by its attenuated virus, 

 and the protection afforded against small-pox by vaccination. 

 And while pathologists still hesitated, he had no doubt of the 

 correctness of Jenner's expression variolic vaccina, or small-pox 

 in the cow. 



It is just a hundred years since Jcmcr made the crucial ex- 

 periment of inoculating with small-pox a boy whom he had 

 previously vaccinated, the result being, as he anticipated, that 

 the boy was quite unaffected. It may be remarked that this 

 ■was a perfectly legitimate experiment, involving no danger to 

 the subject of it. Inoculation was at that time the established 

 practice ; and if vaccination should prove nugatory, the inocu- 

 lation would be only what would liave been otherwise called 

 for ; while it would be perfectly harmless if the hoped-for effect 

 of vaccination had been produced. 



We are a practical people, not much addicted to personal 

 commemorations ; although our nation did indeed celebrate 

 with fitting splendour the jubilee of the reign of our beloved 

 Queen ; and at the invitation of Glasgow the scientific world has 

 lately marked in a manner, though different, as imposing, the 

 jubilee of the life-work of a sovereign in science (Lord Kelvin). 

 But while we cannot be astonished that the centenary of Jenner's 

 immortal discovery should have fiiiled to receive general recog- 

 nition in this country, it is melancholy to think that this year 

 should, in his native county, have been distinguished by a 

 terrible illustration of the results which would sooner or later 

 inevitably follow the general neglect of his prescriptions. 



I have no desire to speak severely of the Gloucester Guardians. 

 They are not sanitary authorities, and had not the technical 

 knowledge necessary to enable them to judge between the teach- 

 ings of true science and the declamations of misguided, though 

 well-meaning, enthusiasts. They did what they believed to be 

 right ; and when roused to a sense of the greatness of their mis- 

 take, they did their very best to repair it, so that their city is 

 said to be now the best vaccinated in her Majesty's dominions. 

 But, though by their praiseworthy exertions they succeeded in 

 promptly checking the raging epidemic, they cannot recall the 



NO. 1403, VOL. 54] 



dead to life, or restore beauty to marred features, or sight to 

 blinded eyes. Would that the entire country and our Legislature 

 might take duly to heart this object-lesson ! 



I low completely the medical profession were convinced of the 

 efficacy of vaccination in the early part of this century, was 

 strikingly illustrated by an account given by Prof Crookshank, 

 in his interesting history of this subject, of several eminent 

 medical men in Edinburgh meeting to .see the (to them) unprece- 

 dented fact of a vaccinated person having taken small-pox. It 

 has, of course, since become well known that the milder form of 

 the disease, as modified by passing through the cow, confers a 

 less permanent protection than the original human disorder. 

 This it was, of course, impossible for Jenner to foresee. It is, 

 indeed, a question of degree, since a second attack of ordinary 

 small-pox is occasionally known to occur ; and vaccination, 

 long after it has ceased to give perfect immunity, greatly 

 modifies the character of the di.sorder, and diminishes its 

 danger. And, happily, in re-vaccination after a certain number 

 of years we have the means of making Jenner's work complete. 

 I understand that the majority of the Commissioners, who have 

 recently issued their report upon this subject, while recognising 

 the value and importance of re-vaccination, are so impressed 

 with the difficulties that would attend making it compulsory by 

 legislation that they do not recommend that course ; although it 

 is advocated by two of their number who are of peculiarly high 

 authority on such a question. I was lately told by a Berlin pro- 

 fessor that no serious difficulty is experienced in carrying out the 

 compulsory law that prevails in Germany. The masters of the 

 schools are directed to ascertain in the case of every child 

 attaining the age of twelve whether re-vaccination has been 

 practised. If not, and the parents refuse to have it done, they 

 are fined one mark. If this does not prove effectual, the fine is 

 doubled ; and if even the double penalty should not prove 

 efficacious, a second doubling of it would follow ; but, as my 

 informant remarked, it is very seldom that it is called for. The 

 result is that small-pox is a matter of extreme rarity in that 

 country, while it is absolutely unknown in the huge German 

 army, in consequence of the rule that every soldier is re- 

 vaccinated on entering the service. Whatever view our Legis- 

 lature may take on this question, one thing seems to me 

 clear : that it will be the duty of Government to encourage by 

 every available means the use of calf lymph, so as to exclude the 

 possibility of the communication of any human disease to the 

 child, and to institute such efficient inspection of vaccination 

 institutes as shall ensure careful antiseptic arrangements, and so 

 prevent contamination by extraneous microbes. If this were 

 done, "conscientious objections" would cease to have any 

 rational basis. At the same time, the administration of the 

 regulations on vaccination should be transferred (as advised by 

 the Commissioners) to competent sanitary authorities. 



But to return to Pasteur. In 1880 he entered upon the study 

 of that terrible but then most obscure di.sease, hydrophobia or 

 rabies, which from its infective character he was sure must be 

 of microbic origin, although no micro-organism could be 

 detected in it. He early demonstrated the new pathological 

 fact that the virus had its essential seat in the nervous system. 

 This proved the key to his success in this subject. One result 

 that flowed from it has been the cause of unspeakable consola- 

 tion to many. The foolish practice is still too prevalent of 

 killing the dog that has bitten any one, on the absurd notion 

 that, if it were mad, its destruction would prevent the occur- 

 rence of hydrophobia in the person bitten. The idea of the b.ire 

 possibility of the animal having been so affected causes an agony 

 of suspense during the long weeks or months of possible 

 incubation of the disease. Very serious nervous symptoms 

 aping true hydrophobia have been known to result from 

 the terror thus inspired. Pasteur showed that if a little 

 of the brain or spinal cord of a dog that had been really mad 

 was inoculated in an appropriate manner into a rabbit, it 

 infallibly caused rabies in that animal in a few days. If, there- 

 fore, such an experiment was made with a negative result, the 

 conchision might be drawn with certainty that the dog had been 

 healthy. It is perhaps right that I should say that the inocula- 

 lation is painlessly done under an anesthetic, and that in the 

 rabbit rabies does not assume the violent form that it does in 

 the dog, but produces gradual loss of power with little if any 

 suffering. 



This is the more satisfactory because rabbits in which the 

 disease has been thus artificially induced are employed in carry- 

 ing out what was Pasteur's greatest triumph, the preventive 



