---- pointed out to Professor Mivart the difficulty in the way of
natural selection, 344

---- his ignorance concerning the earlier history of evolution, 392, 393

Hybridism, Buffon on, 117, 118

Hybrids, sterility of, Lamarck on, and C. Darwin on, 272, 273

IDEAS, the bond or nexus of our, 23, 29, 30

Ignorance, the prevailing, concerning the earlier evolutionists, 61

---- it is easy to hide our, under such expressions as "plan of
creation," or natural selection, 358

Imitation, instinct not referable to, as maintained by Erasmus
Darwin, 202

Immutability of species and design commonly accepted together, 9, 10

Improvements, small successive, in man's inventions, 44, 46,
47, 54, 55, 384

Inaccuracy of thought, C. Darwin accused of, 359

Incipiency, of complex structures, a difficulty in the way of the
Natural selection view of evolution, 21, 22

Incorporate, the designer is, with the organism, 30

Increase, geometrical ratio of Buffon on the, 123

---- Lamarck on, 280

---- Patrick Matthew on, 320, 321

Indefinite, with C. Darwin the variations are, 342, 344

Indifference, I say I am more indifferent than I think I am, whether
mind is or is not the least misleading symbol for the cause that
sustains the universe, 371

Indirect action of conditions of existence according to
Lamarck, 294, 299, 306. (_See_ "Conditions of Existence")

Individuality, Buffon on, 128

---- of buds, Erasmus Darwin on the, 207, 208

---- our, a _consensus_, or full-flowing river, 318

Infallibility, possible results of the doctrine of Papal, 406

Insectivorous plants, Erasmus Darwin on, 206

Instep, ligament that binds the tendons of the, Paley on the, 22

Instinct, present, does not bar its having arisen in reason and
reflection, 53, 54

---- returns to its earlier phase, _i. e._ to reason on the presence
of the unfamiliar, 54, 55, 56

---- and reason, Buffon on, 110-116

---- Darwin, Erasmus, on, 115, 116, 204

---- not referable to imitation, as maintained by Erasmus Darwin, 202

---- is reason become habitual, 203

---- reason perfected and got by rote, 256

---- and reason, Lamarck on, 256, 257, 274

---- referred to experience and memory, by Patrick Matthew, 322

Insult, "Evolution, Old and New," not intended as an insult to men
of science, 392

Interaction of want and power, 44, 45, 47, 217, 218, 221, 300, 323

---- of body and mind, Lamarck on the, 338, 339, 341