REPORT ON ANIMAL PHYSIOLOGY. 101 



to explain the action of the organic machine. Thus, he submitted 

 muscular motion to calculation on the principle of the lever ; ex- 

 plained the action of the heart and the motion of the blood upon 

 hydraulic principles ; and accounted for the secretions from the 

 various diameters of the vessels. The proximate cause of mus- 

 cular motion he asserted to be the rush of nervous fluid from the 

 brain upon the muscular fibre. Bellini and Baglivi espoused the 

 same theory, and extended its application by their writings ; but, 

 as if internally aware of its insufficiency, and proving that they 

 merely reposed in it as that which was least objectionable, they 

 laboured to separate the theory from the practice of medicine. 

 Thus Baglivi was in practice a follower of Hippocrates and of 

 Sydenham. John Bernouilli was a celebrated disciple of this 

 school. He considered the elementary geometry of the Italians 

 insufficient in its application to the animal body, in as much as 

 this represents neither line nor plane either in itself or in the ulti- 

 mate particles into which it can be resolved. Hence he had re- 

 course to the calculus lately invented by Newton and Leibnitz 

 and the theory of curves. His theory of muscular motion gained 

 great celebrity, as well as his application of the analysis to de- 

 termine the decrement- of the body in consequence of the various 

 transpirations and secretions. Another branch of the mathemati- 

 cal school was founded on the Newtonian theory of attraction, 

 and had for its supporters in this country Keill, the Robinsons, 

 Wintringham, and Meade. 



These two schools, as may be well supposed, did not add very 

 much directly to the science as a whole. But they prepared the 

 way. each advancing it according to its own partial views. The 

 intimate structure of parts and their connexions were sedulously 

 ascertained by dissection, by the microscope, by chemical ana- 

 lysis, in order to ascertain the data upon which chemical or mathe- 

 matical constructions were to be founded. It is not unreasonable 

 to attribute to the hypothesis of Willis and of Vieussens, which 

 ascribed the cause of all the sympathies so remarkable in the 

 human body to the physical connexion of parts by means of 

 nerves, that great perfection which the anatomy of the nervous 

 system attained in their hands. 



The followers of the chemical and mathematical schools either 

 overlooked tfie necessity of having recourse to a vital cause for 

 the operations they attempted to explain, or they had recourse to 

 an animating principle as presiding over them. Hence arose what 

 has been termed the dynamic school of phjsiology. In the sy- 

 stem of Stahl the soul not only produces and forms the body, but 

 maintains it in the performance of every voluntary and involun- 

 tary act. Those motions, even, which he allowed to exist exclu- 



