XX 
INTRODUCTION. 
which filled space, gradually condensing, attached themselves to our 
planet, the elements combined, and the globe, during its first igneous 
period, changed, there appeared, at a temperature of not less than 
60° R., the lowest forms of plants, and together with them probably 
the lowest animalculse,—the two so similar in structure and appearance 
that the most careful observation and the deepest scientific research, 
which they require even to this day, have not been able definitely to 
determine their respective lines of demarcation. Convulsions of the 
upper portion of the earth’s crust, conditions of life suddenly ceasing, 
and the consequent necessarily natural and simultaneous extinction 
of living creatures, ended this first organic creation: not so the 
traces; thereby, as it were, confirming from the very outset the 
everlasting law, that nothing in creation is perishable. Upon this, so 
to speak, more or less general Death, follows a new Life,—after the 
first wreck a new creation. Subsequent convulsions, strewing the 
earth with corpses, leave their mark; but still again a new world 
arises from the field of Death. After each Death a nobler Life,—for 
with each resurrection the earth received a more highly developed 
form, though some of the earlier creations returned, or still survived. 
The periods between each of these convulsions we call the days of 
creation,—their length none can determine; neither can any 
assignable division of time during the earth’s creation as yet be 
allotted with certainty. 
Birds had also their periods of death and resurrection. The earth 
preserves to us their remains in proof thereof. Gigantic Birds 
lived in hoary antiquity; they have now disappeared, and are 
forgotten. In the Roc and the Griffon, through dark dreamy myths, 
the last breath of their existence reaches us like an echo. But these 
vanishing spectres of the past are reawakened through a poetic 
medium, and are taken up again in hopeful tones, in the legend of 
the Phoenix,—that mysterious emblem of the resurrection,—which 
teaches that everything subject to the power of death must rise 
again. 
If we measure the age of the earth by its strata we find that Birds 
made their appearance at a very late period; only inferior animals 
are to be found in the strata next the primary rock. Creatures of a 
superior organisation would not have been able to exist there, for, at 
the time of the first plant-world, carbonic acid so pervaded the 
atmosphere that these creatures, at all events, with the exception of 
