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An Adaptation of MICROBE HUNTERS

Gail S. Tucker-Griffith



ABSTRACT

Students reenact scenes from the history of science. The script for a two act play is provided. The first scene depicts the story of Lazzaro Spallanzani. The second act deals with Pasteur and his refutation of spontaneous generation.

Click here to go to an ASM News page about Microbe Hunters.


(Running Time: 25-30 Minutes)

CAST OF CHARACTERS: (Insert Names of Students)

  • Francesco Redi
  • Lazzaro Spallanzani
  • Needham
  • Louis Pasteur
  • UNSUNG HEROES AND FRIENDS: (Insert Names)

  • Mr. Spallanzani, Sr.
  • Dr. Valesnieri
  • Caignard de la Tour
  • Dr. Schwann
  • Mr. Bigo
  • Professor Balard
  • Director: (Insert Name)

  • Prop Crew/Special Effects (F/X): (Insert Names)
  • Redi Experiment
  • Spallanzani Experiment
  • Pasteur Experiment
  • Other
  • Cameraperson: (Insert Name)

  • ACT I: The Life and Times of Lazzaro Spallanzani

    NARRATOR #1:

    To please his father, young Lazzaro Spallanzani pretended to be interested in the law--but during his vacations his mind wandered and his interest in the natural world took over as he watched skipping stones, and animals, and dreamed about understanding the violent fireworks of volcanoes. Lazzaro's father wanted him to study law instead. An old family friend, the scientist Vallisnieri, interceded for him with his father.

    VALLISNIERI (to the senior Spallanzani):

    "Mr. Spallanzani, you are throwing away Lazzaro's talents on the study of law. Your son is going to be a scientist as great as Galileo!"

    NARRATOR #1:

    Spallanzani Senior agreed to allow Lazzaro to attend the University to take up the study of science. At that time it was more respectable and safe to be a scientist than it had been during Leuwenhoek's time. People were no longer persecuted if they questioned superstitions and unproven ideas about nature. At the University, Spallanzani was free'd at last from an endless future of legal wranglings, testing all authority no matter how famous, and getting into associations with every kind of person, from fat bishops, officials, and professors to outlandish actors and minstrels!!! Spallanzani skipped stones over water in earnest, and wrote a brilliant scientific paper on the physics of skipping stones. He became a priest to support himself by saying Mass. In Spallanzani's time, sensible people believed that many animals did not have to have parents--that they might arise as the illegitimate offspring of a disgusting variety of dirty messes. Here, for example, is the recipe for making a swarm of bees: Take a young bull, kill him with a knock on the head, bury him under the ground in a standing position with his horns sticking out. Leave him there for a month, and saw off his horns. Out will fly a swarm of bees! Prompted by such ideas, Spallanzani developed violent notions about whether life could arise spontaneously.

    SPALLANZANI:

    "There must be law and order to the birth of all things. It is absurd to think that things could arise in a haphazard way from out of any old dirty mess. But, how do I prove it?"

    NARRATOR #1:

    Spallanzani happened to find a little known book by a man named Redi. This book told him an entirely new way to tackle the question of how life arises. The fellow who wrote the book did not argue with mere words--he did experiments. Redi showed how even intelligent men believed that flies and maggots could arise out of putrid meat. Spallanzani grew excited as he read about the experiment. He went immediately to his teacher Vallisnieri to explain the wonders of Redi's wo rk.

    SPALLANZANI:

    "Val, listen to this. This fellow Redi has shown that flies do not come from putrid meat."

    VALLISNIERI:

    "Lazzaro--tell me about it. How'd he do that??????"

    SPALLANZANI:

    "Redi took three jars and put some meat in each one. He left one jar open, put a heavy veil over a second one, and the third one he covered with a light veil. He watched the jars and saw flies land on the meat in the open jar. In a little while there were maggots there, and eventually new flies. Then he looked in the jar with the heavy veil over it and there were no flies or maggots in it at all! A very few maggots were on top of the light veil"

    VALLISNIERI:

    "How wonderful! Then it is just a matter of keeping the mother flies from getting to the meat....Of course, the flies may not come from eggs, it may be that sub-visible animalcules arise of themself from rotted meat."

    NARRATOR #2:

    Spallanzani was not satisfied with that answer. The next day he decided to tackle the same question with the microscopic animals. He tried to think of a way to do this. In England another priest-scientist named Needham told how he had taken a quantity of hot gravy from the fire, put it in a bottle, plugged up the bottle VERY TIGHTLY with a cork (so that no animals or their eggs could get in), and done an experiment of is own. He heated the bottle and the gravy in it with the cork in place.

    NEEDHAM:

    "Surely this will kill the little animalcules or their eggs that are still in the flask."

    NARRATOR #2:

    Needham put the cooked flasks with the corks away for several days. Then he pulled the corks. He examined the gravy.

    NEEDHAM :

    "Aha! This gravy is full of animalcules! They arose from the Vegetative force of the gravy since the heat would kill everything and the cork will keep things out."

    NEEDHAM :

    "This is a real experiment showing that life can arise spontaneously from dead stuff!"

    NARRATOR #2:

    Needham made gravies of all sorts of things and had the same result. Europe was in an uproar. Finally someone had proven the hypothesis that living things do not need parents to form. They can arise from nothing!

    NARRATOR #2:

    [Spallanzani enters stage left, talking to himself.]

    But in Italy, Spallanzani was not satisfied. He knit his brows (KNIT BROWS SPALLANZANI), he narrowed his eyes . He exclaimed:

    SPALLANZANI:

    "Animalcules do not arise by themselves! This fine experiment is a fraud--even if Needham does not realize it is." "I must determine a way to show that it is wrong! Why did the animalcules appear? Why?

    NARRATOR #2:

    Suddenly, Spallanzani had a brainstorm. It hit him immediately [ BONG ] that there was a very simple explanation for Needham's results.

    SPALLANZANI:

    "Needham did not heat the bottles long enough, AND he did not plug them tightly enough!"

    NARRATOR #2:

    So Spallanzani took some flasks, scrubbed and washed and dried them carefully, put seeds of various kinds into some, and other things into the others. He added purified water. And his experiment was ready to begin.

    SPALLANZANI:

    "Now, I'll heat these soups for an hour--boiling without stopping. I'll close them up so that there is no doubt that they are sealed by melting the necks of the glass flasks shut even as they boil. That way NOTHING, no matter how small will get into the flasks."

    NARRATOR #2:

    For hours, Spallanzani boiled his flasks, They bumped and danced in the cauldrons of water. He boiled one set for a few minutes, another for a full hour and another for even longer. He made up duplicate sets of stews in flasks--but he corked these with stoppers and did not melt them shut. Then, they were boiled just as the first sets. After a few days he examined their contents.

    [ INSERT SPALLANZANI'S EXPERIMENT HERE ]

    SPALLANZANI:

    "What's this? There are NO animalcules in some of the flasks which had their necks sealed shut. But look! In all of the flasks that were corked, there ARE animalcules! Why are there also animalcules--if only a very few--in the sealed flasks that had been boiled for a few minutes?"

    NARRATOR #2:

    Spallanzani was elated! He had some exciting results to report! As he thought about it, he realized why some of the lightly boiled flasks had a very few animalcules.

    SPALLANZANI:

    "I see! Some animalcules can withstand heat. This is a new and startling discovery."

    NARRATOR #3:

    But in England, Needham responded to this work by saying that the heat also weakened the VEGETATIVE FORCE in the sealed flasks that had been cooked for a long time.

    NEEDHAM:

    "Your experiment does not hold water! You heated the flasks too long and damaged the Vegetative Force of the soups and gravies. They can no longer make little animals."

    NARRATOR #3:

    But Spallanzani sensed victory! He was not to be discouraged.

    SPALLANZANI:

    "I'll show Needham that the vegetative force in the seeds is NOT affected."

    NARRATOR #3:

    Spallanzani again got out his flasks. He made his different soups. He began a new series of experiments. He heated the flasks for different lengths of time. If Needham was right, then the flasks boiled a short time would have many many animalcules. Those boiled a long time would have little or no animalcules.

    SPALLANZANI:

    "Vegetative Force! Nonsense. If you only plug the flasks with corks, the parents can sneak in and grow in there."

    NARRATOR #3:

    Spallanzani looked at the samples days later. He found what he had predicted.

    SPALLANZANI:

    "The flasks with corks all have animalcules. Even those which were boiled for hours. That means that my experiment sealing the flasks is right--microbes come from the air and are necessary for soups to make animalcules. Life DOES not arise from non-living things!"

    A CT II: PASTEUR-- Microbes and the question of spontaneous generation

    NARRATOR #4:

    As a young boy, Louis Pasteur became involved in science. He studied and began conducting research on a number of problems. As he grew up he had seen several people in his village die from rabies. He was curious about why the disease struck so mysteriously. But before becoming involved in this aspect of medicine, he had a more practical problem to solve. In 1837, a Frenchman, Cagniard de la Tour, found out that the material in fermenting beer vats included yeasts that were budding.

    CAGNIARD DE LA TOUR:

    "These yeasts then are alive. They multiply just like other creatures. It must be their life that changes the barley into brew."

    NARRATOR #4:

    Cagniard de la Tour found that without the yeast, beer did not form from the brew. Other scientists also studied questions related to the origins of living things. In Germany, Doctor Schwann, who was the first to describe the cell as the unit of all living things, published a short paper on how to preserve meat:

    SCHWANN:

    "Boil meat thoroughly and put it in a clean bottle. Lead air into it that has passed through red hot pipes, and the meat will remain perfectly fresh for months. But, if you let regular air get at the meat it will immediately begin putrefying and be no good in a day or so. It will smell very bad."

    NARRATOR #4:

    This was an important observation, but it was not fully understood. In France meanwhile, Pasteur was approached by a brewery owner in his town.

    MR. BIGO (Brewery Owner):

    "Louis, we are having trouble with our fermentations. I wonder if you would come over to the brewery and check our vats to see what is wrong."

    NARRATOR #4:

    Pasteur was very interested in this problem. He immediately went over to the brewery to see what was cookin'.

    PASTEUR:

    "Mr. Bigo, after studying the mash from your vats, I find that there are no budding yeasts in the mash. Only single spheres are present and some other animalcules that I have never seen before."

    NARRATOR #5:

    Pasteur was baffled. The new animalcules were smaller than what he was used to seeing. But he eventually demonstrated that the mash was bad and that these new organisms were the problem. Mr. Bigo thanked him for identifying the problem, but posed an interesting question to Pasteur.

    MR. BIGO:

    "Professor Pasteur, tell me, where do our yeasts come from that we have year after year? All over France, we rely on the yeast to work our mash into beer or wine, yet we do not know where they come from."

    NARRATOR #5:

    Pasteur was stopped dead in his tracks. Here was the question that had been cropping up repeatedly and dealt with by many scientists. Yet there was no completely satisfactory answer to it. He puzzled over this question. One day, a friend--Professor Balard, discussed this issue with him. He said:

    PROFESSOR BALARD:

    "Louis, you say you are stuck. You say you do not see how to get air and boiled yeast soup together without getting all sorts of other living things in the yeast soup as well. Why don't you try the trick of putting the yeast soup in a bottle and THEN fixing the opening of the bottle so that dust won't fall in?"

    PASTEUR:

    "But how can I do that?"

    PROFESSOR BALARD:

    "Easy. Take one of your flasks, and put the yeast into it. Next, try to soften the neck of the glass flask with your lamp. Then you stretch the molten neck of the flask out. It will form into a thin tube. To be sure the opening is blocked from things in the air, bend the tube up like a swan bends his neck. Then, leave the bent tube open to the air."

    NARRATOR #5:

    Pasteur was thrilled. This was the material he needed to do his experiment. When he did the experiment, grew yeast in the crook-necked flask--the yeast soup did not become infected with

    PASTEUR (to his friend Balard):

    "I thought it would work. You see, when the air comes back in, the dust and the germs are caught in the crook in the neck of the flask and cannot get to the yeast soup. But how can we prove that that is so?"

    BALARD:

    I am sure that you will do it Louis, you are very persistent"

    PASTEUR:

    "I've got it!"

    NARRATOR #5:

    And with much cheek kissing as is the French habit...PASTEUR said to his friend Balard, "I'll tilt the flask and spill some of the yeast into the crook and then let it fall back into the flask. If what we say is correct, then the yeast broth should grow other animalcules from the dust in the crook of the flask."

    NARRATOR #5:

    Pasteur tried the experiment. Later on at a meeting of the great scientists of the day he exclaimed:

    PASTEUR:

    "Never will the doctrine of spontaneous generation recover the mortal blow that this simple experiment has dealt it."


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