July 19, 1877] 



NATURE 



233 



organism. For hours, and even for days after the opera- 

 tion, these motions persisted ; so that the contrast between 

 the death-like quiescence of the mutilated swimming- 

 bell and the active contractions of the thread-like portion 

 which had just been removed from its margin, was a con- 

 trast as striking as it is possible to conceive. 



These experiments, then, conclusively proved that in 

 the marginal rim of the Meduss; there is situated an in- 

 tensely localised system of nervous centres, or ganglia, 

 to the functional activity of which the rhythmical motions 

 of the swimming-bell are exclusively due. 

 {To be continued.) 



ON ELEMENTARY INSTRUCTION IN 

 PHYSIOLOGY^ 

 'T^HE chief ground upon which I venture to recommend 

 -*■ that the teaching of elementary physiology should 

 form an essential part of any organised course of instruc- 

 tion in matters pertaining to domestic economy, is that a 

 knowledge of even the elements of this subject supplies 

 those conceptions of the constitution and mode of action 

 of the living body and of the nature of health and disease, 

 which prepare the mind to receive instruction from sanitary 

 science. 



It is, I think, eminently desirable that the hygienist and 

 the physician should find something in the public mind 

 to which they can appeal ; some little stock of universally 

 acknowledged truths, which may serve as a foundation for 

 their warnings, and predispose towards an intelligent 

 obedience to their recommendations. 



Listening to ordinary talk about health, disease, and 

 death, one is often led to entertain a doubt whether the 

 speakers believe that the course of natural causation runs 

 as smoothly in the human body as elsewhere. Indications 

 are too often obvious of a strong, though perhaps an un- 

 avowed and half unconscious, undercurrent of opinion 

 that the plienomena of life are not only widely different 

 in their superficial characters and in their practical 

 importance, from other natural events ; but that they do 

 not follow m that definite order which characterises the 

 succession of all other occurrences, and the statement of 

 which 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 know- 

 ledge is the essential preliminary, which is so often 

 noticeable ; and a corresponding laxity and carelessness 

 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 Ueity, and which, therefore, looks with repugnance 

 upon both preventive and curative measures, as alike 

 blasphemous interferences with the will of God. Among 

 ourielves, the " Peculiar People " are, 1 believe, the only 

 persons who hold the like doctrine in its integrity, and 

 carry it out with logical rigour. But many of us are old 

 enough to recollect that the administration of chloroform 

 in assuagement of the pangs of childbirlh was, at its 

 introduction, strenuously resisted upon similar grounds. 



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

 which I have referred is the full expression, docs 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 anything exceptional about these phenomena 

 receives not a particle of support from any known fact. 



the Domeslic Economy Congress, by Prof. Hu.xicy, 



On the contrary, there is a vast and an increasing mass 

 of evidence that birth and death, health and disease, are 

 as much parts of the ordinary stream of events as the 

 rising and setting of the sun, or the changes of the moon ; 

 and that the living body is a mechanism the proper work- 

 ing 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 hy- 

 gienist and of the physician is to know the range of these 

 modifiable conditions, and how to influence them towards 

 the maintenance of health 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 know- 

 ledge, 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 charact-^ristic of physiology — the difficulty of 

 the subject begins beyond the stage of elementary know- 

 ledge, and increases with every stage of progress. While 

 the most highly trained and best furnished intellect may 

 find all its resources insufficient when it strives to reach 

 the heights and penetrate into the depths of the problems 

 of physiology, the elementary and fundamental truths can 

 be made clear to a child. 



No one can have any difficulty in comprehending the 

 mechanism of circulation or respiration, or the general 

 mode of operation of the organ of vision ; though the 

 unravelling of all the minutiae of these processes may, 

 for the present, baffle the conjoined attacks of the most 

 accomplished physicists, chemi;ts, and mathematicians. 

 To know the anatomy of the human body, with even an 

 approximation to thoroughness, is the work of a life, but as 

 much as is needed for a sound comprehension of element- 

 ary physiological truths may be learned in a week. 



A knowledge of the elements of physiology is not only 

 easy of acquirement, but it miy be made a real and 

 practical acquaintance with the facts, as far as it goes. 

 The subject of study is always at hand in oneself. The 

 principal constituents of the skeleton, and the changes of 

 form of contracting muscles, may be felt through one's 

 own skin. The beating of one's heart, and its connection 

 with the pulse may be noted ; the influence of the valves 

 of one's own veins may be shown ; the movements of 

 respiration may be observed ; while the wonderful pheno- 

 mena of sensation afford an endless field for curious and 

 interesting self-study. The prick of a needle will yield, in 

 a drop of one's own blood, material for microscopic 

 observation of phenomena which lie at the foundation of 

 all biological conceptions ; and a cold, with its concomitant 

 coughing and sneezing, may prove the sweet uses of 

 adversity by helping one to a clear conception of what is 

 meant by " reflex action." 



Of course, there is a limit to this physiological self- 

 examination. But there is so close a solidarity between 

 ourselves and our poor relations of the animal world, that 

 our inaccessible inward parts may be supplemented by 

 their.-. A comparative anatomist knows that a sheep's 

 heart and lungs, or eye, must not be confounded with 

 those of a man ; but so far as the comprehension of the 

 elementary facts of the physiology of circulation and of 

 respiration and of vision goes, the one furnishes the 

 needful anatomical data as well as the other. 



Thus, it is quite possible to give instruction in elemen- 

 tary physiology in such a manner as not only to confer 

 knowledge, which, for the reason I have mentioned, is 

 useful in itself ; but to serve the purposes of a training in 

 accurate observation, and in the methods of reasoning of 

 physical science. But that is an advantage which I 



