168 HABIT AND INTELLIGENCE. [cHAP. 



Motor true not of tlie motor actions of animals only, but of those 

 cfimbing ^f Vegetables as well : for instance, those remarkable 

 plants. motions of some climbing plants tliat Darwin ^ has lately 

 described, tbe tendrils of which swing about until they 

 touch something, and then clasp themselves round it. 

 Here there is no possibility of conscious purpose on the 

 part of the plant itself, and yet the motions of its tendrils 

 are as truly habitual and instinctive as those of a serpent's 

 body, or of a chameleon's feet and tail, in grasping the 

 Motor and branches that they climb. Thus all mental and all motor 

 habits actions are to be classed as habitual, excepting only those 

 which, in man and some of the most intelligent animals, 

 are directed by a voluntary impulse in pursuit of a con- 

 scious purpose. 

 Formative But a still more extensive use of the word habit is 

 sanctioned by usage, and, in my opinion, with perfect 

 accuracy. Physicians speak of a habit of body ; and 

 botanists speak of the habit of a plant, meaning by that 

 expression such characters as whether the stem is herba- 

 ceous or woody, whether the leaves are fleshy or thin, &c. 

 Characters of this kind belong not to the motor but to the 

 formative functions — not to the animal, but to the vegeta- 

 tive life ; yet I think it is perfectly accurate to class such 

 characters as habits, and to say that they come under the 

 laws of habit. I believe that all classes whatever of vital 

 functions come under these laws, whether the functions 

 are formative, motor, or sensory; whether vegetative, 

 animal, or mental. Formative and motor actions are 

 inseparably connected. To mention one instance out of 

 an innumerable number : — " Ampelopsis quinquefolia, or 

 Virginian the Virginian creeper, avoids the light, uniformly seeking 

 creeper, ^^^.-j^ crevices On broad flat surfaces, as a wall, a rock, or 

 the trunk of a tree. The tips of the tendrils, brought 

 into contact with such a surface, swell out, and form in 

 a few days those well-known discs or cushions by which 

 the plant firmly adheres to its support." ^ The moving 

 of the tendrils in search of some suitable dark crevice 



1 See the Quarterly Jonmal of Science, April 1866, pp. 257, 258. 



2 Ibid. p. 258. 



