oduced by the processes fulfilled in plants. Their
exact constitution is not known; analysis shows that they contain
approximately: Carbon 50-55%, Hydrogen 6.9-7.5%, Nitrogen 15-19%,
Oxygen 20-24%, Sulphur 0.3-2.0%. Venous blood contains in 100
volumes: Nitrogen, 13; Carbonic Acid, 71.6; Oxygen, 15.3. Arterial
blood: Nitrogen, 14.5; Carbonic Acid, 62.3; Oxygen, 23.2.

"Nitrogenous compounds in general, are extremely prone to
decomposition; their decomposition often involving a sudden and
great evolution of force. We see that substances classed as ferments
... are all nitrogenous ... and we see that even in organisms and
parts of organisms where the activities are least, such changes as
do take place are initiated by a substance containing nitrogen....
We see that organic matter is so constituted that small incidental
actions are capable of initiating great reaction and liberating
large quantities of power.... The seed of a plant contains
nitrogenous substances in a far higher ratio than the rest of the
plant; and the seed differs from the rest of the plant in its
ability to initiate ... extensive vital changes--the changes
constituting germination. Similarly in the bodies of animals ... in
every living vegetal cell there is a certain part that contains
nitrogen. This part initiates these changes which constitute the
development of the cell.... It is a curious and significant fact
that, in technology, we not only utilize the same principle of
initiating extensive changes among comparatively stable compounds by
the help of compounds much less stable, but we employ for the
purpose compounds of the same general class. Our modern method of
firing a gun is to place in close proximity with the gunpowder which
we choose to decompose or explode, a small portion of fulminating
powder, which is decomposed or exploded with extreme facility, and
which on decomposing, communicates the consequent molecular
disturbances to the less easily decomposed gunpowder. When we ask
what this fulminating powder is composed of, we find that it is a
nitrogenous salt."--Spencer.

11 Of course, the geometric progression does not represent _precisely_
the law of human progression; it is here employed because it is
familiar and serves, better perhap