Beginnings in Other Lands


Overthrow of Doctrine of Spontaneous Generation
           The beginning of wisdom is found in doubting;
           by doubting, we come to the question, and by
           seeking we may come to the truth.     PIERRE ABELARD
  In 1667, only nine years after Kircher's publication, the simple direct
investigations of Redi2' in Arezzo, Italy, cast discredit on Kircher's
statements and those of others as to the sources of the "worms"
in
decomposing matter. Even the experimental portion of the long conflict
is so involved that we can cite only this beginning with Redi and the
dramatic chapter closing with Tyndall and Pasteur. To test the view
that "worms" arise from decomposing animals or plants, Redi placed
several kinds of flesh in boxes, observed the decay, and watched the
maggots appear and change into adult insects. At times he thought he
saw flies dropping ova on the meat, a possible source of the maggots.
To test this hypothesis, he placed fresh meat in three sets of small jars,
the first left open, the second covered with fine gauze, and the third
covered tightly with parchment. The meat in all the jars became de-
cayed attracting flies by the odors. In a short time, maggots appeared
in the open jars, and these later developed into flies. In the second
series maggots developed on the surface of the gauze, but not in the
meat below. The meat in the third series covered with parchment de-
cayed, but no maggots appeared. He carried out many similar experi-
ments with flies on different fruits and vegetables tracing the develop-
ment of the ova through maggots to adult insects of several species
  and thus laid a careful foundation for his famous dictum omne vivum
  ex vivo.
    More exacting experiments by Spallanzani (I729-99), a century
  later, and increasingly critical studies of Schulze, Schwann, and
  Schrdder in the middle of the nineteenth century apparently settled the
  question.
  ANTONY VAN LEEUWENHOEK AND HIS SUCCESSORS
              There is nothing too little for so little a
              creature as man. It is by studying little things
              that we attain the great art of having as little
              misery and as much happiness as possible.
                        JOHNSON TO BOSWELL FOR HIS PRIVATE JOURNAL
     In the meantime, however, Antony van Leeuwenhoek (16 32-1723)
  had come onto the scene and other microscopists such as his fellow


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