268 DESIGN IN NATURE 



various kinds. They may be voluntary or involuntary, or partly the one and partly the other. They are volun- 

 tary when volition or its representative comes into operation, as when an animal with or without a nervous 

 system, as we know it, throws itself upon food ; they are involuntary in the established rhythms and reflexes, as 

 witnessed in the lungs, alimentary canal, and heart ; and they are mixed, as in swallowing, defascation, urmation, 

 parturition, &c. The involuntary rhythms and reflexes are originally the products of protoplasm and rudimentary 



structures. 



They are conferred for the wisest of purposes, namely, for the appropriation and assimilation of food, for 

 growth, reproduction, and the hke. It is a significant fact that the involuntary rhythms and so-called reflexes 

 of plants and animals precede and are the parents of what may be designated the voluntary rhythms, as they occur 

 in the voluntary muscles. Curiously enough, the latter, in many cases, after frequent repetition and from the force 

 of habit, merge into the former. There is a give and take as between the voluntary and involuntary muscles and 

 movements. Thus walking, which, at the outset, is a voluntary movement acquired by laborious effort, becomes, 

 after a time, automatic. The same is to be said of musical and other performances where habit and unconscious 

 cerebration are at work. 



Of course it may be maintained that rhythms and reflexes, however produced originally, are more or less auto- 

 matic. This, within hmits, is true ; but it is important to point out that, at the outset, they are, in every instance, 

 the product of lowly substances and organisnas, which act directly or at first hand — that is, as apart from irritation, 

 stimulation, and every form of circumlocation. The rhythms and reflexes, as a matter of fact, under all circum- 

 stances, retain much of their spontaneity and power of independent action. Repetition and habit deepen, rather 

 than account for, their original pecuharities. As illustrations of natural normal actions at first hand as compared 

 with unnatural abnormal action at second hand I may mention the following. If a piece of dry bread falls or is 

 suddenly drawn into the fauces, it is at once forcibly ejected. No such result follows if the bread be insaUvated 

 and swallowed in the ordinary way. If a strong aperient be administered, the alimentary tract is thrown into 

 violent action, often accompanied with griping pain, and the bowel forcibly and quickly evacuated. No such pheno- 

 mena occur in natural alimentation and defsecation. If a diuretic be given, the amount of urine is increased and 

 frequent micturition follows. The drug stimulates the secretion and expulsion of urine but causes neither. In 

 like manner, ergot of rye increases but does not cause the rhythmic action of the uterus in parturition. The 

 effect of stimuh is to quicken and increase normal action. Artificial stimuh, if continuously applied, destroy the 

 tolerating, accommodating, and retaining power of the viscera. If by any chance the fauces, aUmentary canal, 

 bladder, and uterus be inflamed (and irritable as a consequence) the unnatural results obtained by stimulation are 

 exaggerated. 



The movements of living things are to be regarded as the result of inherent endowments : they are means to 

 ends, and the outcome of Design. They are part of the equipment of life, and caimot be traced to irritability of 

 constitution or external stimulation. 



Life without rhythms and reflexes could not manifest itself, could not adequately perform its various functions. 

 It is no explanation of these functions to say that the substances and structures which produce them are so formed 

 that a stimulus apphed to them causes them to work perfectly ; as in the several compartments of the heart, which 

 open and close alternately. The opening and closing movements are diametrically opposed to each other, and no 

 single stimulus could effect the double and opposite result. 



The same may be said of hght entering the eye, which it is claimed produces the opening and closing of the 

 eyelids in winking. If hght be the stimulus which causes the eyehds to close, it cannot possibly at the same time 

 cause them to open. The double movement can only be explained by original endowment. 



All plants and animals are fitted by nature to do certain things : they are superior to their surroundings ; they 

 take in and retain certain elements and reject others ; they act upon their surroundings, near and remote ; the 

 surroundings in turn acting upon them to the extent of calhng forth new powers, which result in modifications to meet 

 altered circumstances. The modifications, however, are produced by the plants and animals themselves, and are 

 in no sense accidental. They are not the result of mere extraneous stimulation. If plants develop thick rinds and 

 thick leaves in tropical, dry climates, it is to prevent the evaporation of the juices on which their life depends. If 

 animals in the arctic regions develop layers of blubber under the skin and thick furs over it, it is for the purpose of 

 preventing the escape of bodily heat ; this being necessary to their comfort and even their existence. The mere 

 presence of heat or cold, as such, cannot be accredited with the production of the thick rinds and leaves of plants, 

 or the blubber and furry coats of animals. These have their origin in the original endowments and powers of plants 

 and animals respectively. Slight changes and modifications in plants and animals, considering the unstable 

 nature of the physical universe which supphes them with food and a home, were inevitable, but these were fore- 

 seen and provided for, and plants and animals have, within themselves, the wherewithal to modify all or any of 



