pasteur and vaccines -- 7/22/20
Today's selection -- from Scientist for Life by Ernest Baumler. In the late 1800s, the famed Louis Pasteur significantly improved the vaccine process than had been discovered by Edward Jenner in 1796:
"Since 1879, [Louis] Pasteur had been conducting intensive studies into the so-called 'chicken cholera' and had discovered, when some cultures were inadvertently left standing for several weeks, that the microorganisms grew best in an infected broth. Then, he infected a few chickens with the old and apparently very weak culture and found, much to his surprise, that the chickens briefly hung their heads but nevertheless survived the infection. When he infected the same chickens with a fresh culture shortly afterwards, they had obviously become immune, as they showed no further reaction whatever. The dangerous organisms that had rapidly killed other chickens proved harmless to the birds he had previously 'immunized.' Thus it was that one of the basic principles for protective inoculation was discovered, namely the technique of using weakened pathogens to mobilize the host organism against intact pathogens of the same type, thereby rendering them harmless and protecting the infected human or animal against a corresponding infection.
|Jean-Baptiste Jupille receiving a rabies
vaccination administered by a member
of Pasteur's team while Pasteur himself
witnesses the event.
"Addressing the Academy of Sciences on June 13, 1881, Pasteur summarized his experiments on vaccination against anthrax:
We now possess vaccines for anthrax which can prevent this fatal disease without themselves having a fatal action-living vaccines which can be produced at will, dispatched anywhere without deterioration and, lastly, produced by a method which seems likely to be applicable to diseases generally, since it has already been used to discover a vaccine against chicken cholera. Owing to the special nature of the circumstances I mentioned, the discovery of anthrax vaccination, considered from the purely scientific viewpoint, represents a notable advance over Jenner's smallpox serum, for never before has this been achieved by means of experimentation.
Pasteur next turned his attention to another disease known since ancient times, rabies. Pasteur first determined that the disease could be transmitted. He did this by transferring diminutive particles of brain or spinal cord from rabid animals to healthy animals. Pasteur obtained his first toxin for inoculation from a rabid stray dog and injected the 'street virus,' as he called it, into healthy rabbits. The first infected rabbit died after a fortnight, while other animals injected with toxin from their respective predecessors died after increasingly brief periods. Yet, it proved possible to immunize dogs against rabies with the toxin from the rabbits. Even when bitten directly by rabid dogs, the immunized animals remained unharmed.
"France followed Pasteur's experiments with rapt interest. By that time he had become a national hero, a member of the Academie Française, and a holder of the Grand Cross of the Legion of Honor besides other awards from many crowned heads of Europe. Having achieved his aspirations and received such fame, he could now ill afford to make mistakes. Dare he proceed from immunizing dogs to immunizing humans? On July 6, 1885, the decision was forced upon him by a distraught mother from Alsace whose nine-year-old son had been bitten fourteen times by a rabid dog two days previously. Doctors had told her that her son, Josef Meister, had no hope of survival unless Pasteur dared to immunize him at once. Pasteur, who was a chemist and not a doctor, hastily conferred with a number of medical experts. On the evening of that same day he injected vaccine into the boy's buttocks. Further injections of increasingly virulent material followed. The boy tolerated the injections well, but Pasteur remained deeply worried. What if something went wrong? Only after thirty anxious days did Pasteur know for certain that Josef Meister had been cured. The boy was able to return home."