Histonal selection, [66].
Huxley, Thomas, [12].
Hypna, [22].
Hypotheses, nature of, [5] et seq.
Ids, their theoretical character, [7].
Imagination, its function in science, [4].
"Imperfect" formations, [81].
Individual variations, [73] et seq.
Inertia, law of organic, [15].