[9] This term is borrowed from the well-known works of Galton on composite photographs, which are scarcely more than twenty years old. Huxley in his book on Hume (Chapter IV.) appears to be the first who introduced it into psychology, as shown by the following passage: “This mental operation may be rendered comprehensible by considering what takes place in the formation of compound photographs—when the images of the faces of six sitters, for example, are each received on the same photographic plate, for a sixth of the time requisite to take one portrait. The final result is that all those points in which the six faces agree are brought out strongly, while all those in which they differ are left vague; and thus what may be termed a _generic_ portrait of the six is produced. Thus our ideas of single complex impressions are incomplete in one way, and those of numerous, more or less similar, complex impressions are incomplete in another way; that is to say, they are generic.... And hence it follows that our ideas of the impressions in question are not, in the strict sense of the word, copies of those impressions; while at the same time they may exist in the mind independently of language.” Romanes employs the word “recept” for “generic images,” as marking their intermediate place between the “percept” which is below, and the “concept” which is above them. [10] For details see Romanes, _Animal Intelligence_, Chapters III. and V. As to the probability of their possessing means of communication for assistance in their co-operative labors see below, Chapter II. [11] Romanes. _Animal Intelligence_, Chapter III. [12] C. Lloyd Morgan. _Animal Life and Intelligence_, Chapter IX., p. 364. [13] Houzeau, _Etudes sur les facultés mentales des animaux_, Vol. II., p. 264 et seq. The same author gives an example of generalisation in bees. [14] Darwin, _The Descent of Man_, Vol. I., Chapter III. [15] Romanes, _loc. cit._, Chapter XVII. [16] At the end of the passage in question there is an extraordinary account of the arithmetical powers of a dog which Lubbock explains by “thought reading.” I omit this instance, since we are deliberately rejecting all rare or doubtful cases. [17] _Mental Evolution in Man_, Chapter III., p. 58. [18] J. Sully, _The Human Mind_, I., 460. The author gives excellent diagrams to represent the difference in the two cases. For reasoning from particular to particular, cf. also J. S. Mill, _Logic_, II., Chapter III., p. 3; Bradley, _Logic_, II., Chapter II., p. 2. [19] _In re_ analogy, consult Stern’s monograph, _Die Analogie im volksthümlichen Denken_, Berlin, 1894. [20] _Three Introductory Lectures on the Science of Thought, delivered at the Royal Institution_, appendix, p. 6, letter 4; Chicago, 1888. It should, however, be remembered that the writer who thus uses the logic of images has a mind preformed by the logic of signs: which is not the case with animals.