38 so _ ANNUAL REPORT. 
and still others select such unpromising soils as gravel, fragments of rocks, — 
or even iron andlead. So far as our present knowledge goes, they are never 
produced in any other way than from the spores of the same species. These 
are infinitesimally small. The air is full of them, of all kinds and descrip- 
tions. They are deposited everywhere, and are excluded with the greatest 
difficulty, if indeed, they can be excluded at all. 
The mind is like the eye; it can only grasp the middle ground of vision. 
In that beautiful band of colors, the solar spectrum, there is more heat 
towards the red, and more chemical power towards the violet end. They 
extend far outside the visible colors. Light, heat and actimism are all pro- 
duced by the same kind of waves, differing only in size. Heat and the red — 
are produced by larger waves than actimism and the violet. Green is the 
medium. The eye recognizes only those wave lengths between and includ- 
ing the red and violet. Outside these the waves are too large or too small to 
produce the sensation of light. 
So with the mind: Wecan have no definite idea of infinite space @r of 
endless torment. The figures $1,000,000,000,000 give us no conception of 
the amount represented. In the opposite direction it is the same. With 
our powerful microscopes we view wonderfully small things; but it is only 
a step towards the minute. Rub your hand over a bar of soap and-rinse it 
in a tub of pure water. The whole will take a blue tinge. The coloris dis- 
tinct, but the particles of soap which produce it are far beyond the power of 
the best microscope. Another experiment will push the question still 
farther. Whena match is burned, a pungent, poisonous gas is produced. It 
is sulphurous acid. It consists of one part of sulphur vapor by volume, and 
two parts of oxygen, chemically combined. Light destroys the B pens 
force, and loosens the two elements. In a dark room fill a large glass tube, 
having glass ends, with this gas. Through the tube pass a single ray of light 
from any source. At first, nothing will be seen. The particles of the gases 
are not large enough to reflect light. At the end of fifteen minutes, a slight 
blueish tinge will appear, increasing until the particles of sulphur are all 
released. Now the light began to act upon the compound gas immediately, 
and the particles of sulphur have been growing for fifteen minutes. But 
with the best microscope in the world they cannot be seen separately. The 
mind can form no conception of them when first liberated. 
Many experiments have been tried, to prove spontaneous generation. All 
sorts of solids and liquids have been sealed up and carefully watched for 
signs of life. They are generally found in the form of some kind of fungous 
growth, but there is always a doubt about the total exclusion of all germs. 
Fungi are always rapid in growth, and rapid in decay. In a night a small 
army of dwarf umbrellas will appear in a door-yard. In as short a time 
they disappear. They are vastly more important than is generally supposed. 
We favor their growth as the yeast plant, the vinegar plant, and the mush- 
rooms which we eat; we oppose their growth as smut, rust, potato and timber 
rot. Many of them are indirectly useful to us in hastening the decay of 
organic matter. New life is supported at the expense of the old, and 
together both are returned to the original soil. They are the scavengers 
among plants. It is not yet proven that such infectious diseases as diph- 
theria, cholera, &c., are due to growth of fungi. They are frequently 
present, almost always in diphtheria, but bad cases of both have occurred 
where no traces of fungi could be found. One thing is certain; the best 
