ne or
of several preceding generations, are required. The son may not resemble
the father, but the grandfather, and in some instances, the likeness
re-appears only in latter generations. Agassiz states: "Alternate
generation was first observed among the Salpae. These are marine
mollusks, without shells, belonging to the family Tunicata. They are
distinguished by the curious peculiarity of being united together in
considerable numbers so as to form long chains, which float in the sea,
the mouth(_m_) however being free in each.

[Illustration: Fig. 2. ]

[Illustration: Fig. 3. ]

"Fig. 2. The individuals thus joined in floating colonies produce eggs;
but in each animal there is generally but one egg formed, which is
developed in the body of the parent, and from which is hatched a little
mollusk.

"Fig. 3, which remains solitary, and differs in many respects from the
parent. This little animal, on the other hand, does not produce eggs,
but propagates, by a kind of budding, which gives rise to chains already
seen in the body of their parent(a), and these again bring forth
solitary individuals, etc."

It therefore follows that generation in some animals require? two
different bodies with intermediate ones, by means of which and their
different modes of reproduction, a return to the original stock is
effected.

UNIVERSALITY OF ANIMALCULAR LIFE.--Living organisms are universally
diffused over every part of the globe. The gentle zephyr wafts from
flower to flower invisible, fructifying atoms, which quicken beauty and
fragrance, giving the promise of a golden fruitage, to gladden and
nourish a dependent world. Nature's own sweet cunning invests all living
things constraining into her service chemical affinities, arranging the
elements and disposing them for her own benefit, in such numberless ways
that we involuntarily exclaim,

"The course of Nature is the art of God."

The microscope reveals the fact that matter measuring only 1/120000 of
an inch diameter may be endowed with vitality, and that countless
numbers of animalcules often inhabit a single drop of stagnant water.
These monads do not vary in form, whether in motion or at rest. The life
of one, even, is an inexplicable mystery to the philosopher. Ehrenberg
writes: "Not only in the polar regions is there an uninterrupted
development of active microscopic life, where larger animals cannot
exist, but we find that those minute beings collected in the Antarcti