Page 60 - My FlipBook

FIFTH LECTURE.

Historical.
December 12, 1900.
In my last lecture I made an effort to give you some idea
of the place in Nature to which micro-organisms belong and
of their function in the economy of the universe.
This morning I want first to sketch briefly some history
of the development of our knowledge of micro-organisms.
This subject is comparatively new and we may say it is still
in its infancy. It has not been many years since we began to
obtain accurate knowledge of micro-organisms ; indeed, it
has all been done, or nearly all, during my lifetime and in-
terest in this subject, so that I have seen the development.
True, some work had been done earlier, but it was not
very accurate work. Even two hundred years ago some ob-
servations were made and published that, as we look back
now, we can regard as fairly accurate work, but not on micro-
organisms—on some of the lower animalculae and fungi,
however. In 1838 Schwann published the first of what may
be termed accurate studies of the yeast fungus or the bud-
ding fungi, those organisms that produce alcoholic fermenta-
tion. With the instruments he then had he was enabled to
see the yeast cells, to watch their budding, watch their
growth and watch the results of their growth, and he made
out that they were the agents of alcohoHc fermentation.
Such a supposition was a great violence to the ideas of scien-
tific men at that time, and Schwann was at once attacked by
Liebig, one of the most powerful chemists of the age.
Schwann could not bring sufficient evidence of the correct-
ness of his work to combat such a man as Liebig, he was
ridiculed and beaten, and for some years there seemed to be
great danger that his discoveries would be lost. Chemists
of that day, and for two hundred years earlier, had regarded
the fermentations as produced by, or a consequence of, mole-
cular vibrations in matter of unstable composition, and the
supposition was that the character of these molecular vibra-
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