436 HISTORY OF PHYSIOLOGY. 



Moreover, besides the interest which the mere speculative faculty gave 

 to this study, the Art of Healing added to it a great practical value ; 

 and the effects of diseases and of medicines supplied new materials and 

 new motives for the reasonings of the philosopher. 



In this manner anatomy or physiology may be considered as a 

 science which began to be cultivated in the earliest periods of civiliza- 

 tion. Like most other ancient sciences, its career has been one of 

 perpetual though variable progress ; and as in others, so in this, each 

 step has implied those which had been previously made, and cannot 

 be understood aright except we understand them. Moreover, the 

 steps of this advance have been very many and diverse ; the cultivators 

 of anatomy have in all ages been numerous and laborious ; the subject 

 is one flf vast extent and complexity ; almost every generation had 

 added something to the current knowledge of its details ; and the 

 general speculations of physiologists have been subtle, bold, and 

 learned. It must, therefore, be difficult or impossible for a person 

 who has not studied the science with professional diligence and pro- 

 fessional advantages, to form just judgments of the value of the dis- 

 coveries of various ages and persons, and to arrange them in their due 

 relation to each other. To this we may add, that though all the dis- 

 coveries which have been made with respect to particular functions or 

 organizations are understood to be subordinate to one general science, 

 the Philosophy of Life, yet the principles and doctrines of this science 

 nowhere exist in a shape generally received and assented to among 

 physiologists ; and thus we have not, in this science, the advantage 

 which in some others we have possessed; of discerning the true 

 direction of its first movements, by knowing the point to which they 

 ultimately tend ; of running on beyond the earlier discoveries, and 

 thus looking- them in the face, and reading their true features. With 



O O 



these disadvantages, all that we can have to say respecting the history 

 of Physiology must need great indulgence on the part of the reader. 



Yet here, as in other cases, we may, by guiding our views by those 

 of the greatest and most philosophical men who have made the sub- 

 ject their study, hope to avoid material errors. Nor can we well 

 evade making the attempt. To obtain some simple and consistent 

 view of the progress of physiological science, is in the highest degree 

 important to the completion of our views of the progress of physical 

 science. For the physiological or organical sciences form a class 

 to which the classes already treated of, the mechanical, chemical, and 

 classificatory sciences, are subordinate and auxiliary. Again, anotlu-r 



