Salvarsan

The Discovery of Salvarsan ("606").—Salvarsan, or "606," is a chemical compound used in the modern treatment of syphilis. It was announced to the world by Paul Ehrlich, its brilliant discoverer, in December, 1910. Ehrlich and his Japanese co-worker, Hata, had some years before been impressed with the remarkable effect certain dyes had on the parasites infesting certain animals and which resemble the germs that cause the African sleeping sickness in man. When one of these dyes was dissolved and injected into the blood of the sick animal, the dye promptly picked out and killed all the parasites, but did not kill the animal. Dyes are very complex chemical substances and certain of them seem to have an affinity for germs. It occurred to Ehrlich that if a substance could be devised which was poisonous for the germ and not for the patient it might be possible to prepare a specific for a given disease, acting as quinin does in malaria. By combining a poison with a dye it might be made to pick out the germs and leave the body unharmed.
Paul Ehrlich [1854-1915] Paul Ehrlich [1854-1915]
(From "Year Book of Skin and Venereal Diseases," 1916, vol. ix. "Practical Medicine Series," Year Book Publishers, Chicago.)

The poison which had already been shown to be especially effective in killing germs like those of[Pg 71] syphilis was arsenic. The problem was to get arsenic into such a combination with other chemical substances that it would lose its poisonous quality for man, but still be poisonous for the spirochete of syphilis. Ehrlich and Hata began to make chemical compounds of arsenic in the laboratory with chemical substances like the dyes. As the compounds grew more complex they were tested on animals and some of them found to have the qualities for which their inventors were searching. Some of them are even used at the present time in the treatment of certain diseases. The six hundred and sixth compound in this series, when tested on syphilitic animals, was found to be extraordinarily efficient in killing the germ of syphilis, even when used in quantities so small as not to injure the animal. Among other things, there could be no better example of the importance of animal experiment in medicine. If the cause of syphilis had not been known, and the disease not given to animals, the discovery of salvarsan might never have been made. After extensive experiments on syphilitic rabbits, which showed that the drug could be given safely in amounts large enough to cure the animal at a single dose, it was tried on man, two physicians, Drs. Hoppe and Wittneben, volunteering for the test. When it was found that the drug did them no harm, it was used on syphilitic patients for the first time. As soon as its remarkable effect on the disease in them was fully established, Ehrlich announced the discovery before the medical society of Magdeburg, and the results were published in one of the most[Pg 72] important of the German medical journals. Ehrlich then sent out from his own laboratory several thousands of doses of the new drug to all the principal clinics and large hospitals of the world for an extended trial. It was not until the results of this trial became apparent that he permitted its manufacture on a commercial scale. There could scarcely be a more ideal way of introducing a new form of treatment than the one adopted by Ehrlich, or one better surrounded by all the safeguards that conservatism could suggest.

The Mistaken Conception of "Single Dose Cure."—In the light of his experience with salvarsan in animals, Ehrlich hoped to accomplish the cure of syphilis in man by a single dose of the new drug, as he had been able to cure it in rabbits. All the earlier use of salvarsan in the treatment of syphilis was carried out with this idea in view, and the remarkable way in which the symptoms vanished before the large doses used encouraged the belief that Ehrlich\'s ideal for it had been fulfilled. But it was not long before it was found that syphilis had a stronger hold on the human body than on animals, and that patients relapsed after a single dose, either as shown by the blood test or by the reappearance, after varying intervals, of the eruption or other symptoms of the disease. Unfortunately, the news of the discovery of salvarsan, and with it Ehrlich\'s original idea that it would cure syphilis by a single dose, had gotten into the newspapers. Numbers of syphilitics treated with it have been deceived by this notion into believing themselves cured. In those whose symptoms[Pg 73] came back in severe form, the trouble was, of course, found out. But there are at the present time, undoubtedly, many persons who received a single dose of salvarsan for a syphilis contracted at this time, and who today, having never seen any further outward signs of the disease, believe themselves cured, when in reality they are not. In the next twenty years the introduction of salvarsan will probably result in a wave of serious late syphilis, the result of cases insufficiently treated in the early days of its use. It was not long before it was found that not one but several doses of salvarsan were necessary in the treatment of syphilis, and soon many physicians of wide experience began to call in mercury again for help when salvarsan proved insufficient for cure. At the present time the use of both mercury and salvarsan in the treatment of the disease is the most widely accepted practice, and seems to offer the greatest assurance of cure.

The Value of Salvarsan.—Salvarsan has done for the treatment of syphilis certain things of the most far-reaching importance from the standpoint of the interests of society at large. It has first of all made possible the control of the contagious lesions of the disease. Secondly, as was said before, it has made possible the cure of the infection in the primary stage, before it has spread from the starting-point in the chancre to the rest of the body. To understand how it accomplishes these results it is important to understand its mode of action.

The Action of Salvarsan.—It will be recalled that Ehrlich planned salvarsan to kill the germs of syphilis,[Pg 74] just as quinin kills the germs of malaria. It was intended that when the drug entered the blood it should be carried to every part of the body, and fastening itself on the spirochetes, kill them without hurting the body. This is seemingly exactly what the drug does, and it does it so well that within twenty-four hours after a dose of it is given into the blood there is not a living germ of syphilis, apparently, in any sore on the body. If the same thing happened in all the out-of-the-way corners of the body, the cure would be complete. The natural result of removing the cause of the disease in this fashion is that the sores produced by it heal up. They heal with a speed and completeness that is an even greater marvel than the action of mercury. The more superficial the eruption, the quicker it vanishes, so that in the course of a few days all evidence of the disease may disappear. This is especially true of the grayish patches in the mouth and about the genitals, which have already been described as the most dangerously contagious lesions of syphilis. It is evident, therefore, that to give salvarsan in a case of contagious syphilis is to do away with the risk of spreading the disease in the quickest and most effective fashion. It is as if a person with scarlet fever could be dipped in a disinfecting bath and then turned loose in the community without the slightest danger of his infecting others. How much scarlet fever would there be if every case of the disease could be treated in this way? There would be as little of it as there now is of smallpox, compared to the wholesale plagues of that disease which used to kill[Pg 75] off the population of whole towns and counties in the old days. If we could head off the crops of contagious sores in every syphilitic by the use of "606," syphilis in the same way would take a long ............