Feb. 1902.] BOTANICAL SOCIETY OF EDINBURGH 177 



SO on, SO that in estimating the lenuth of A there is a 

 pre-existent disposition to see it short, limited, etc., 

 evidently the effect on the notion (length of A) due to 

 the (mental) functional inertia of the preceding idea^ — 

 " end reached," " bounded," " limited," etc. Similarly, the 

 short diverging lines on the ends of B suggest "extension," 

 " outwards," " boundaries not fixed,'' and so on, hence 

 v^e carry over into the next idea — length of B — by 

 mental functional inertia some disposition to see B " long," 

 " going outwards," or " upwards," " not bounded," and so 

 on. Since in the notion, length of A by itself, there 

 is a latent tendency to under-estimation, and in the notion, 

 length of B, a tendency to over-estimation, we at once 

 judge A shorter than B when the two ideas are present 

 to the mind simultaneously. 



The well-marked tendency to think, say, or do what has 

 been thought, said, or done before — to yield to habit, to 

 the familiar — is nothing other than the expression of the 

 functional inertia of psychic activity. Quite a number of 

 people, for instance, will say " thirty or forty " for " thirty 

 or fewer " when in reading aloud they meet the latter 

 phrase. The mental condition in hypnotism, where the 

 suggestion has started a train of thought adhered to with 

 astonishing tenacity, and worked out to its uttermost 

 consequences in spite of all possible distractions, is surely 

 well expressed as the inertia of psychic activity : the 

 inertia — the obliviousness — has been by artificial means 

 morbidly increased for the time being : it is an insuscepti- 

 bility to all but a few stimuli, and may amount to actual 

 sensory paralysis. So, too, it is mental inertia that 

 causes certain persons to be refractory to hypnotic in- 

 fluence. But examples could be indefinitely multiplied. 

 Are not bigotry and fanaticism respectively the inertia 

 of psychic rest and the inertia of psychic movement ? 

 Superstition and an unenlightened dislike to change are 

 surely due to the inertia of psychic rest. The lingering 

 of superstition from generation to generation is an example 

 of psychic inertia in the race — all failure to respond to 

 intellectual environment, must arise from mental inertia. 

 In the child-mind it is owing to the feeble degree of 

 inertia of psychic rest and of psychic activity that it 



