. A brief epitome of the list of some
of his more important discoveries conveys some idea, of his fertility of
mind as well as his industry. In 1780 he discovered lactic acid,(7) and
showed that it was the substance that caused the acidity of sour
milk; and in the same year he discovered mucic acid. Next followed the
discovery of tungstic acid, and in 1783 he added to his list of useful
discoveries that of glycerine. Then in rapid succession came his
announcements of the new vegetable products citric, malic, oxalic, and
gallic acids. Scheele not only made the discoveries, but told the
world how he had made them--how any chemist might have made them if
he chose--for he never considered that he had really discovered any
substance until he had made it, decomposed it, and made it again.

His experiments on Prussian blue are most interesting, not only because
of the enormous amount of work involved and the skill he displayed in
his experiments, but because all the time the chemist was handling,
smelling, and even tasting a compound of one of the most deadly poisons,
ignorant of the fact that the substance was a dangerous one to handle.
His escape from injury seems almost miraculous; for his experiments,
which were most elaborate, extended over a considerable period of time,
during which he seems to have handled this chemical with impunity.

While only forty years of age and just at the zenith of his fame,
Scheele was stricken by a fatal illness, probably induced by his
ceaseless labor and exposure. It is gratifying to know, however, that
during the last eight or nine years of his life he had been less bound
down by pecuniary difficulties than before, as Bergman had obtained for
him an annual grant from the Academy. But it was characteristic of the
man that, while devoting one-sixth of the amount of this grant to his
personal wants, the remaining five-sixths was devoted to the expense of
his experiments.

LAVOISIER AND THE FOUNDATION OF MODERN CHEMISTRY

The time was ripe for formulating the correct theory of chemical
composition: it needed but the master hand to mould the materials into
the proper shape. The discoveries in chemistry during the eighteenth
century had been far-reaching and revolutionary in character. A brief
review of these discoveries shows how completely they had subverted
the old ideas of chemical elements and chemical compounds. Of the four
substances earth, air, fire, and water, for many centuries be