[1.] The nervous system is composed of units of structure called neurones or nerve cells. "If we could see exactly the structure of the brain itself, we should find it to consist of millions of similar neurones each resembling a bit of string frayed out at both ends and here and there along its course. So also the nerves going out to the muscles are simply bundles of such neurones, each of which by itself is a thread-like connection between the cells of the spinal cord or brain and some muscle. The nervous system is simply the sum total of all these neurones, which form an almost infinitely complex system of connections between the sense organs and the muscles."
The word synapses, meaning clasping together, is used as a descriptive term for the connections that exist between neurone and neurone.
[2.] This is synonymous with James's Involuntary Attention, Angell's Non-Voluntary Attention, and Titchener's Secondary-Passive Attention.
[3.] Educational Psychology, Briefer Course, pp. 194-5.
[4.] Thorndike, Psychology of Learning, p. 194.
[5.] How We Think, p. 6.
[6.] The Psychology of Thinking, p. 98.
[7.] How We Think, p. 66.
[8.] How We Think, pp. 69-70.
[9.] Psychology of Thinking, p. 291.