and in the laboratory in the endeavor to pierce still further with trained insight into the mysteries of nature. And these are their results.
No one realizes more than the zoologist that his knowledge is incomplete. No one can see more clearly than he that his intellect evolves, like the great sweeping tide of things and events—the nature he studies and of which he is but a conscious atom. The investigator soon learns to withhold final judgment, agreeing with Clifford that the primary conditions for intellectual development are the plasticity and openness of mind that dogmatism and finality destroys. The end of zoology can not be until the end of all knowledge.
Conscious, then, of the impossibility of reaching absolutely final knowledge, why does the investigator continue to search the world of nature as he does? Because of that ingrained and insatiable human curiosity to learn, because of the human discontent with the attained. Antæus-like, every fresh contact with the world of law and order infuses new energy into his veins for further endeavor. "Und es treibt und reisst ihn fort, rastlos fort. . ." not, it is true, in the wandering blindness of Schiller's huntsman, for his human vision is aided by the instrument of scientific method with which he can almost perceive the infinitely great and the infinitely small.
Glorying in the great achievements of his science, reveling like the mathematician in the ordered assemblage of related and organized knowledge, the student of zoology joins his fellows yet again for a renewed attack upon the distant ramparts of the unknown, deriving courage and inspiration from the motto: Ignoramus, in hoc signo laboremus.