=Voluntary Attention.=--Dr. Carpenter speaks of launching himself by a determined _effort_. This _effort_ characterizes what we called _active or voluntary attention_. It is a feeling which everyone knows, but which most people would call quite indescribable. We get it in the sensorial sphere whenever we seek to catch an impression of extreme _faintness_, be it of sight, hearing, taste, smell, or touch; we get it whenever we seek to _discriminate_ a sensation merged in a mass of others that are similar; we get it whenever we _resist the attractions_ of more potent stimuli and keep our mind occupied with some object that is naturally unimpressive. We get it in the intellectual sphere under exactly similar conditions: as when we strive to sharpen and make distinct an idea which we but vaguely seem to have; or painfully discriminate a shade of meaning from its similars; or resolutely hold fast to a thought so discordant with our impulses that, if left unaided, it would quickly yield place to images of an exciting and impassioned kind. All forms of attentive effort would be exercised at once by one whom we might suppose at a dinner-party resolutely to listen to a neighbor giving him insipid and unwelcome advice in a low voice, whilst all around the guests were loudly laughing and talking about exciting and interesting things. _There is no such thing as voluntary attention sustained for more than a few seconds at a time._ What is called sustained voluntary attention is a repetition of successive efforts which bring back the topic to the mind. The topic once brought back, if a congenial one, _develops_; and if its development is interesting it engages the attention passively for a time. Dr. Carpenter, a moment back, described the stream of thought, once entered, as 'bearing him along.' This passive interest may be short or long. As soon as it flags, the attention is diverted by some irrelevant thing, and then a voluntary effort may bring it back to the topic again; and so on, under favorable conditions, for hours together. During all this time, however, note that it is not an identical _object_ in the psychological sense, but a succession of mutually related objects forming an identical _topic_ only, upon which the attention is fixed. _No one can possibly attend continuously to an object that does not change._