September 23, 189;] 



NA TURE 



511 



anthrax. They are refractory to this disease and possess 

 a remarkable immunity to it. Having reflected on this strange 

 fact I framed the hypothesis that the cause of the immunity 

 of the Algerian sheep, which are absolutely similar from the 

 anatomical and zoological point of view to French sheep, 

 depended upon chemical substances contained in the blood, 

 and that in consequence we might hope to confer immunity 

 on French sheep by transfusing into them the blood of the 

 Algerian sheep. It is, however, difficult to make experiments 

 on sheep. Therefore, with my friend Hericourt, who has been 

 throughout these researches my tireless fellow worker, I took 

 animals of two difterent species, the common victims of 

 physiologists — rabbits and dogs. 



Just at that time we had been studying a microbe nearly 

 related to the staphylococcus albus, the staphylococcus pyo- 

 septicus, which in rabbits produces enormous subcutaneous 

 swellings when injected under the skin and causes death in 

 twenty-four to thirty-six hours. The dog, on the other hand, 

 seems to be almost refractory to inoculation with this microbe. 

 We therefore attempted to transfuse the blood of the normal 

 dog into rabbits by intravenous injection, but this operation 

 did not succeed, for the transfusion of dog's blood into the 

 veins of the rabbit even in a dose of only lo gm. rapidly causes 

 death. 



In then occurred to us to resort to peritoneal transfusion in 

 place of intravenous transfusion. In this way we were able 

 to introduce into the organism of the rabbit 50 or 60 gm. of 

 dog's blood, and had the good fortune to see the experiment 

 succeed completely. Rabbits transfused with the blood of 

 the normal dog survived the inoculation of the microbe for four 

 or five days, and rabbits transfused with the blood of a dog 

 vaccinated against the microbe did not die, and were in fact 

 hardly ill at all. 



This experiment, which was made on November 5, 1888, 

 is, as it seems to me, the very basis of serum therapeutics ; 

 it in fact proves that the blood of animals refractory to a disease 

 contains chemical bodies which counteract the effects of the 

 specific pathogenic microbe of the disease. We understood its 

 importance from the first, and having established the general 

 pathological principle, we resolved to apply it to a disease of 

 man. 



For several days, then, Hericourt and I debated the question 

 whether we should experiment with one or other of the three 

 diseases — anthrax, diphtheria, or tuberculosis. Unfortunately 

 we decided for tuberculosis. Its microbe is easily cultivated, 

 and, as you know, it produces greater ravages among men and 

 animals than any other disease. We set to work at once, but, 

 as you will understand, time was required before we could 

 obtain definite results. Still, in a year's time we were able to 

 show that the injection of dog's blood into rabbits retarded 

 enormously the development of tuberculosis. It was, neverthe- 

 less, necessary to pass from experimental physiology to human 

 therapeutics. Taking advantage of an observation of Bou- 

 chard's to the effect that the serum of refractory animals is as 

 active as the whole blood, we were able to inject the serum in 

 tuberculous diseases. The first sero-therapeutic injection was 

 made by us on December 6, 1889. 



At first we had for a space great hope. Yes, in truth, for 

 several weeks we believed that we had discovered the heroic 

 treatment of tuberculosis. For several weeks the various 

 patients that we had under treatment found that their strength 

 was renewed, that their appetite returned, that their weight 

 increased, and that cough and expectoration disappeared almost 

 completely. But, alas, it was no more than a transient improve- 

 ment. A month or a month and a half later the pitiless disease 

 resumed its course, and the sero-therapeutic treatment turned 

 out to be inefficacious. Happily, while by the most diverse 

 plans we were in vain searching for a method of treating tuber- 

 culosis by serum, a German experimenter, Behring, after study- 

 ing the effects of the serum of refractory animals upon diphtheria, 

 showed (in 1892) that this serum is wonderfully efficacious in 

 the treatment of the disease. He applied the serum method of 

 treatment not only to diphtheria, but also to tetanus, and, at 

 first in animals and afterwards in man, he obtained results which 

 were really marvellous. Gentlemen, you know the rest, and I 

 need hot tell you that this sero-therapeutic method, improved 

 and popularised by Roux in 1894, is now a treatment without 

 compare. The statistics on this head are absolutely conclusive. 

 The mortality of diphtheria, which was 45 per cent., has fallen 

 to 15 per cent. That means for the city of Paris alone an annual 



NO. 1456. VOL. 56] 



saving of about 1000 human lives ; for the whole of France 

 nearly 10,000 lives. We may take the same proportion for 

 Italy, Germany, England, the United States, Canada, and 

 Russia, and may estimate the number of infants which serum 

 therapeutics snatch from death at about 50,000. 



In other diseases the results of serum therapeutics have been 

 much mpre open to criticism, and it would be necessary in 

 order to arrive at a satisfactory conclusion to discuss them in 

 detail. I cannot attempt to do this here, for it would be an 

 abuse of your patience. I will content myself by venturing the 

 opinion that serum-therapy has not said its last word. The 

 organism is endowed with a marvellous power of resisting the 

 poisons secreted by microbes. It sets to work in its turn to 

 secrete counter poisons which neutralise the poisons secreted by 

 the microbe. The antitoxins of the organism combat the toxins 

 of the parasite, and in the future the art of serum therapeutics 

 will be to seek in these resisting organisms the antitoxins 

 fabricated by their cells. 



Medicine and Experimental Science. 

 Thus on whatever side we turn we find that medicine has 

 always been guided by experimental science. By experiment 

 and by science it is compelled to march forward. This was 

 true in the time of Harvey, for that immortal physiologist had 

 to meet the opposition of physicians. This was true also in 

 the time of Lavoisier, when by a few decisive experiments 

 he proved the chemical nature of the phenomena of life. But 

 how much more true is it at the present time since Pasteur 

 has by experiment laid open a whole world, and has warranted 

 us in conceiving the widest hopes for the future of medicine ? 



The parts of the man of science and of the physician are very 

 different. The physician ought to be conservative, applying 

 methodically the teaching and the precepts \yhich he has 

 received. He has no right to experiment upon his patients, 01 

 to permit human life or human suffering to be risked on fantastic 

 theories. But the man of science ought to be a revolutionist. 

 He ought not to be content with the doctrines which he has 

 been taught. The opinion of the master ought to be but a light 

 weight upon his mind. He ought to seek on every hand for 

 facts which are new and even improbable. Darwin says some- 

 where that he had made the experiments of a fool, and often it 

 is right to attempt that which appears contradictory to all the 

 most received and classical opinions. Without this spirit of 

 ; adventure, without this scientific daring which opens up new 

 I horizons there is no progre.ss. 



The task of the explorer or of the pioneer is not that of the 



\ physician. He ought to be careful to keep himself abreast of 



all scientific progress in order that his patients may have the 



I benefit of it, but he cannot advance the progress of science, 



: save within restricted limits. Having no right to experiment, 



he is almost powerless to solve the difficult problems which 



arise. 



It is the duty of the chemists, the physicists, and above all 

 the physiologists, to guide medicine into the new ways. They 

 have not to take the heavy responsibility of a human life upon 

 their shoulders, and nothing ought to check their audacity. 

 You, gentlemen, have not the right thus to be audacious : you 

 need prudence and moderation, and, convinced as I am of the 

 power of experimental science, I still think that the applica- 

 tions which the chemists and the physiologists suggest to you 

 should only be accepted with considerable caution. It costs 

 us nothing, after a few experiments which have succeeded fairly 

 well, to say to the physician, " Try that on your patients." You 

 know very well that our responsibility is nil, and that the 

 ancient axiom prima non nocere, an axiom which ought to be 

 your strict rule of conduct, does not in any way apply to us. 

 You see, therefore, that it would be unjust to make it a matter 

 of reproach to physicians and surgeons that they have not 

 made great scientific discoveries. This is not their mission. It 

 is theirs to relieve human suffering, and to seek among new 

 scientific truths that one which is most proper to relieve or to 

 cure the sick. 



Nor can I understand how any one should have wished 

 to create an ar>tagortism between medicine and science. To 

 suppose that they are in contradiction is to show that we under- 

 stand nothing about either the one or the other. It is not 

 reasonable to assert that the one is superior or inferior to the 

 other ; they are different in their means and in their ends. 

 They are mutually complementary, and both are equally, 

 necessary. 



