CONSTRUCTION OF THE PEDIGREE, 37 
employing the empirical results of embryology, palzon- 
tology, and anatomy for supplementing each other, we 
arrive at an approximate knowledge of “the Natural 
System,” which, according to our views, is the pedigree of 
organisms. It is true that our human knowledge, in all 
things fragmentary, is especially so in this case, on account 
of the extreme incompleteness and defectiveness of the 
records of creation. However, we must not allow this to 
discourage us, or to deter us from undertaking this highest 
problem of biology. Let us rather see how far it may even 
now be possible, in spite of the imperfect state of our 
embryological, paleontological, and anatomical knowledge, 
to establish a probable scheme of the genealogical relation- 
ships of organisms. 
Darwin in his book gives us no answer to these special 
questions of the Theory of Descent; at the conclusion he 
only expresses his conjecture “that animals have de- 
scended from at most only four or five progenitors, and plants 
from an equal or less number.” But as these few aboriginal 
forms still show traces of relationship, and as the animal 
and vegetable kingdoms are connected by intermediate tran- 
sitional forms, he arrives afterwards at the opinion “that 
probably all the organic beings which have ever lived on 
the earth have descended from some one primordial form, 
into which life was first breathed by the Creator.” Like 
Darwin, all other adherents of the Theory of Descent have 
only treated it in a general way, and not made the attempt 
to carry it out specially, and to treat the “ Natural System ” 
actually as the pedigree of organisms. If, therefore, we 
venture upon this difficult undertaking, we must take up 
independent ground. 
