ENVIRONMENT 241 



To take other examples. Wholesome food administered to a healthy animal produces no discomfort in the 

 stomach or alimentary canal. The feeling engendered is one of comfort and satisfaction, and not of irritation or 

 pain. Administer to the same animal an irritating drug and soon the stomach and bowels are in an agony of pain. 

 In such a case there is the artificial stimulation (the drug) and the consequent irritation or pain produced by the 

 action of the drug. But (and here comes the crux) neither the stimulation nor the irritation are natural, and they 

 do not exist in the normal condition. 



The muscular twitching and rigid tetanic condition produced by the continuous administration of strychnine 

 is not normal muscular action ; neither is the relaxed, flabby muscular condition produced by the inhalation of 

 chloroform. The strychnine unnaturally exalts the muscular function, and the chloroform unnaturally depresses 

 it. Similarly, the brain may be excited by the drinking of alcohol and other stimulants, or it may be calmed and 

 soothed by the administration of opium and other narcotics. Neither the alcohol nor the opium produces a per- 

 fectly healthy brain function. The stimulant, as a matter of fact, produces the irritation and excitement which 

 are otherwise non-existent. 



If nature is to be studied satisfactorily she must be watched in her simple, normal manifestations, and not in 

 her abnormal, complex conditions, when she is hacked about and tortured by various external stimuh. 



The simplest plants and animals (by preference the transparent ones) yield the best results. 



In making these remarks I have no desire to disparage the important results obtained by a judicious use of 

 vivisection. These have been at once interesting, instructive, and useful. Neither do I wish to set aside the 

 valuable results obtained by cUnical research in cases of disease ; disease acting as a distorted mirror to health. 

 My object is to distinguish between the natural operations and functions of plants and animals, in which neither 

 irritability nor stimulation is present, and the abnormal functions of plants and animals, where irritability and 

 stimulation are artificially induced, or are a consequence of disease. 



In the case of cell plants and animals where next to no differentiation obtains, the various functions of feeding, 

 assimilating, excreting, and reproducing are performed in the simplest manner, as apart from irritabihty and stimu- 

 lation. The lowest plant and animal forms are sensitive, and act spontaneously in certain directions — that is, they 

 are not controlled to any extent by outside influences. What is true of plants and animals is also true of tissues 

 and organs. The involuntary muscles in animals, on which so much depends — say the cardiac, respiratory, and 

 ahmentary muscles — are not, in the normal condition, irritable or jogged into activity by stimuh. On the contrary, 

 they are independent, self-acting structures, whose functions are to take in, retain, and transmit blood, air, and food 

 respectively. The blood does not act as a stimulus to the heart, the air to the lungs, and the food to the alimentary 

 canal. If the blood, air, and food acted as stimuli they could not be retained, as well as taken in and given out at 

 intervals or rhythmically. The secretory and excretory organs also act spontaneously and independently. Secretion 

 and excretion go on so long as the body is in a healthy condition. The muscles, glands, and other structures form 

 part of a Uving mass, and every part of the mass discharges its own particular function, separately and conjointly, 

 as apart from irritability and extraneous stimulation. The combined action of the mass represents the hfe and 

 aggregate endowments of the individual. On the spontaneous, independent action of the units depends the 

 integrity and well-being of the plant and animal ahke. If plants and animals had to depend for their existence on 

 an elaborate system of artificial stimulation, it goes without saying that mishaps and accidents of the most serious 

 character would continually occur. As a matter of fact, the so-called vegetative functions of animals are, for the 

 wisest of purposes, placed beyond the control of the animals. The involuntary functions of the body are, in a 

 sense, more important than the voluntary ones. They are so, as far as mere hfe is concerned. 



§ 47. Environment. 



The subject of environment is closely associated with the theory of irritability and artificial stimulation. It 

 is held by many that environment furnishes a stimulus which causes plants and animals to modify their constitu- 

 tions, their organs, and their general shape and appearance throughout the ages, and makes them what they are at 

 the present day. It is even asserted that environment produces the sense organs and the organs of locomotion. 



According to this view, environment is a leading factor in the production of every conceivable difference in 

 plants and animals ; plants and animals being regarded as living plastic things, which are acted upon by their sur- 

 roundings nolens vokns, or in spite of themselves. Environment is vaunted as superior to plants and animals ; 

 these being, at best, mere living automata, with no discriminating or directive power at their disposal. The dead 

 surroundings are supposed to shape and determine the destinies of living plants and animals respectively. The 

 theory is the invention of the mechanical school of physiologists. According to this school externahties form the 

 skin with its sensory nerves ; odoriferous substances the sense of smell ; sapid substances that of taste ; sound that 



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