454 



THE POPULAR SCIENCE MONTHLY.— SUPPLEMENT. 



system. But certain plants may also not only 

 exhibit symptoms of irritation or sensitiveness 

 when touched, but may act upon their sensations 

 — a feature well exemplified by the drooping 

 leaflets and leaf-stalk of the sensitive-plant, by 

 the closure of the leaf of the Venus's-flytrap, and 

 by definite movements of contraction observed 

 in other plants, resulting from alterations in tem- 

 perature. In plants, it is almost needless to re- 

 mark, no nervous system has been demonstrated 

 to exist ; and no botanist has even suggested the 

 possibility of the existence of nervous tissues 

 within the limits of the vegetable creation. Yet, 

 tested by the acts of their lives, we might truly 

 say to such plants, with Shakespeare — 



" . . . . sense you have, 

 Else could you not have motion ; " 



and, judging from the sensitiveness of the plants 

 just mentioned, the conclusion appears inevitable 

 that plants possess means for receiving and for 

 acting upon sensations, and that in this light they 

 may be fitly compared with the hydra and all 

 lower animals in which a nervous system has not 

 been demonstrated to exist. 



It is perfectly clear that the acts of these 

 plants, and of such animals as the hydra and 

 sea-anemone, must be considered of a purely 

 automatic kind. We cannot reasonably suppose 

 that consciousness, or a knowledge of why or 

 how the acts are performed, plays any part in 

 the life-history of such forms. And, even if it be 

 maintained that mere sensation and conscious- 

 ness in this case are identical or closely allied, 

 the latter quality must be so far removed in 

 its nature from the consciousness of humanity 

 as to render the comparison quite inadmissible. 

 The hydra and its neighbors are in truth auto- 

 mata pure and simple, in that they are stimu- 

 lated by outward circumstances and respond to 

 such stimuli without possessing any appreciation 

 of the why and wherefore of any act of their 

 lives. 



But that automatic acts may represent the 

 whole life, or a very large share of the actions, 

 of animals much higher than these polyps, can 

 readily be demonstrated. A centipede, for ex- 

 ample, when cut in halves, will exhibit lively 

 and independent movements in each half of its 

 body — a fact readily* explained when we note 

 that each joint of the animal's body possesses 

 a nerve-centre which supplies the surround- 

 ing parts with powers of movement. And, if 

 the central portion of the nervous system of 

 the animal be destroyed while its body remains 

 intact, the front pox'tion of the body and the 



front-legs together with the legs lying behind 

 the destroyed portion will continue to push the 

 animal forward. Here the action of the hinder 

 legs is purely automatic. But in the insect-class 

 we find many examples of automatic acts, which 

 at first sight actually seem to suggest the devel- 

 opment of a high intelligence. The young in- 

 sect, just liberated from its chrysalis state, per- 

 forms at once and perfectly all the operations 

 of its life. And even in the case of the won- 

 derful operations exemplified by the ants, bees, 

 and their allies, we find examples of automatism. 

 The acts of these insects are in reality determined 

 by surrounding conditions ; and each insect, des- 

 titute of all previous knowledge, enters upon 

 its duties and discharges them with unerring 

 skill, immediately after its birth or when it has 

 attained its full development. Here, therefore, 

 there can be no intelligent appreciation or 

 consciousness of the nature of the duties per- 

 formed. Indeed, as Dr. Carpenter has well re- 

 marked in speaking of the adaptation of such 

 insects to their duties, " the very perfection of 

 the adaptation, again, is often of itself a suffi- 

 cient evidence of the unreasoning character of 

 the beings which perform the work ; for, if we 

 attribute it to their own intelligence, we must 

 admit that this intelligence frequently equals, if 

 it does not surpass, that of the most accom- 

 plished human reasoner." 



Turning lastly to the investigation of man's 

 actions as a type of those of higher animals gen- 

 erally, we find that physiology makes us ac- 

 quainted with the performance of many auto- 

 matic acts and movements in the common exist- 

 ence of humanity. The earliest acts of the 

 infant are purely automatic; they are performed 

 without the slightest appreciation of their mean- 

 ing, and without any intelligent conception of 

 their order and succession, that order and suc- 

 cession being really' determined by the outward 

 or physical conditions of life. The person who 

 walks along the street absorbed in a reverie or 

 day-dream, but who nevertheless and all uncon- 

 sciously to himself avoids his neighbors and the 

 lamp-posts, is so far an automaton in that the 

 complicated muscular movements of his limbs 

 and the general equilibrium of the body are 

 being coordinated independently of his knowl- 

 edge and will. And very many other examples 

 might be cited in support of the allegation that 

 automatic acts and movements play a very im- 

 portant part in the existence of higher animals. 



Thus we may hold it to be fully proved that 

 automatism has a veritable existence, and really 



