ELEMENTARY INSTRUCTION IN PHYSIOLOGY. 669 



acterizes the succession of all other occurrences, and the statement of 

 Avhich we call a law of Nature. 



Hence, I think, arises the want of heartiness of belief in the value 

 of knowledge respecting the laws of health and disease, and of the 

 foresight and care to which knowledge is the essential preliminary, 

 Avhich is so often noticeable ; and a corresponding laxity and careless- 

 ness in practice, the results of which are too frequently lamentable. 



It is said that, among the many religious sects of Russia, there is 

 one which holds that all disease is brought about by the direct and 

 special interference of the Deity, and which, therefore, looks with re- 

 pugnance upon both preventive and curative measures, as alike blas- 

 phemous interferences with the will of God. Among ourselves, the 

 " Peculiar People " are, I believe, the only persons who hold the like 

 doctrine in its integrity, and carry it out with logical rigor. But 

 many of us are old enough to recollect that the administration of 

 chloroform in assuagement of the pangs of childbirth was, at its in- 

 troduction, strenuously resisted upon similar grounds. 



I am not sure that the feeling, of which the doctrine to which I 

 have referred is the full expression, does not lie at the bottom of the 

 minds of a great many people who would yet vigorously object to 

 give a verbal assent to the doctrine itself. However this may be, the 

 main point is that sufficient knowledge has now been acquired of vital 

 phenomena to justify the assertion that the notion that there is any- 

 thing exceptional about these phenomena receives not a particle of 

 support from any known fact. On the contrary, there is a vast and 

 an increasing mass of evidence that birth and death, health and dis- 

 ease, are as much parts of the oi'dinary stream of events as the rising 

 and setting of the sun, or the changes of the moon ; and that the liv- 

 ing body is a mechanism the proper working of which we term health ; 

 its disturbance, disease ; its stoppage, death. The activity of this 

 mechanism is dependent upon many and complicated conditions, some 

 of which are hopelessly beyond our control, while others are readily 

 accessible and are capable of being indefinitely modified by our own 

 actions. The business of the hygienist and of the physician is to 

 know the range of these modifiable conditions, and how to influence 

 them toward the maintenance of healtli and the prolongation of life ; 

 the business of the general public is to give an intelligent assent, 

 and a ready obedience based upon that assent, to the rules laid down 

 for their guidance by such experts. But an intelligent assent is an 

 assent based upon knowledge, and the knowledge which is here in 

 question means an acquaintance with the elements of physiology. 



It is not difficult to acquire such knowledge. What is true, to a 

 certain extent, of all the physical sciences, is eminently characteristic 

 of physiology the difficulty of the subject begins beyond the stage 

 of elementary knowledge, and increases with every stage of progress. 

 While the most highly-trained and best-furnishqd intellect may find 



