160 JBxkads from Dr. Yeat s's 



the geographical map of a country, we see its cities delineated, its 

 rivers, mountains, and valleys painted in different colours, its 

 various districts described and defined, but we gain no knowledge 

 therefrom of the customs, polity, and laws by which the inhabitants 

 are governed. The same observation will apply with equal force 

 to anatomical knowledge. We may be well acquainted with the 

 structure of the different viscera, with the position of the glands, 

 with the distribution of the ^blood-vessels, and the course of the 

 nerves ; but such knowledge however deep, such research however 

 recondite and laborious, will not teach us how the functions are 

 performed, or become deranged, nor upon what principles the 

 secretions are elaborated. We can raise no superstructure upon 

 this basis explaining the cause and effects of nervous energy, or of 

 the phenomena of healthy and diseased actions. The body is the 

 mere machine upon which the vital laws act ; it affords no know- 

 ledge of the nature of them. The physician can only gain this by 

 experience, observation, and long inquiry, and by that habit of just 

 reasoning, which, derived from a liberal education, is applied to the 

 patient investigation of symptoms. The knowledge of the nature and 

 effects of remedies preceded the knowledge of anatomy ; and some 

 of them indeed still remain, from the earliest ages, recorded as 

 valuable in our materia medica. Well has an ingenious friend of 

 mine observed, it would seem that anatomy is to the science of 

 physic what arithmetic is to algebra j we must know individuals 

 and their combinations before we can abstract, and though a very 

 important branch, is only one of the many which compose the tree : 

 in fact, after many years employed in discovering what anatomical 

 pursuits can do in the progress of the healing art, we have also 

 discovered what it cannot do, and the result will lead us back with 

 some profit indeed to the patient investigation of symptoms and 

 their remedies. 



Soon after that valuable discovery which has deservedly immor- 

 talized the name of Harvey, a new impulse and direction were given 

 to the investigation of disease. The physicians busied themselves 

 throughout Europe by multiplied experiments on dead "and living 

 animals to discover the causes and effects of the healthy and morbid 

 conditions of the body. As long as they confined themselves to 

 the facts they witnessed in the different structures of the body, and 

 in detailing the different appearances they discovered, considerable 

 addition was made to sound and useful learning ; but a mechanical 

 tnode of explanation soon arose, in accounting for the phenomena 

 of the diseased and healthy functions, which led to the most absurd 



