Vlll 



PREFACE 



physiology, U-ing the science of life, is to be regarded as an autonomous 

 and independent study; in other words, that it is to be cultivated for its 

 own sake, and not merely for its applications to the practice of medicine. 

 If we look at the subjects with which he dealt, and which were in part 

 published under the name of "Lemons sur les phe'nomenee de la vie c<miniuns 

 aux animaux et aux vegetaux," we obtain some idea of what Bernard under- 

 stood by general physiology. We find fermentation, nutrition, combustion, 

 protoplasm, irritability and contractility, respiration, and so forth, all treated 

 from a wide and comprehensive point of view. 



A notable passage from Sprat's "History of the Royal Society" (17--, 

 p. l'4."i) is of interest in this connection. The book is, it may be remembered, 

 in great part an apology for the existence of a society for the purpose of 

 making experimental "It is stranger that we are not able to inculcate into 

 the minds of many men the necessity of that distinction of my Lord Bacon's, 

 that there ought to be experiments of iiyht, as well as of fruit. It is their 

 usual word, What solid good will come from thence ? They are indeed to be 

 commended for being so severe exactors of goodness. And it were to be 

 wished that they would not only exercise this vigour about i;q runouts, but 

 on their own fires and actions, that they would still question with themselves, 

 in all that they do ; what solid good will come from thence ? But they are to 

 know that in so large and so various an art as this of c.' [> rlm> ids, there are 

 many degrees of usefulness: some may serve for real and plain / /<-/// 

 without much delight : some for teaching without apparent profit, some for 

 light now, and for use hereafter ; some only for ornament and curinalh/. If 

 they will persist in contemning all experiments, except those which bring 

 \\ith them immediate gain and a present harvest, they may as well cavil at 

 the providence of God, that he has not made all the seasons of the year, to 

 be times of moiuing, reaping, and vintage." A particularly striking case of the 

 practical value of pure abstract laboratory work is to be found in the electric 

 waves of Hertz, which were referred to in the first edition of Karl IVaisi.ii '> 

 " Grammar of Science " as of no practical application, but before the second 

 edition appeared, they were used for wireless telegraphy (see Pearson, 1911, 

 p. 30). Again, Tyndall points out (1870, p. 43), in reference to the great 

 practical use now made of Faraday's electrical discoveries, " that if Faraday 

 had allowed his vision to be disturbed by considerations regarding the 

 practical use of his discoveries, those discoveries would never have been 

 made by him." 



Although most of the problems treated in the present volume are common 

 to tall living organisms, a few are included on account of their importance to 

 a very large number of organisms, notwithstanding the fact that they are not, 

 strictly speaking, of a "general" nature. The fundamental properties of the 

 nervous system may be instanced. 



It will be seen that the scope of general physiology is not identical with 

 that of comparative physiology. This latter is sometimes apt to become in 

 great part a description of functions peculiar to certain lower organisms, even 

 when they throw no light on the activities of the human body, which are, 

 after all, the most vitally interesting and important problems presented to 

 the physiologist. Practically all the questions dealt with by general physio- 

 logy apply both to man and to all living creatures, animal, or plant. In 



