68 Borelli arid the Influence [lect. 



progress in the beginning of the seventeenth century under 

 Galileo and his school. Borelli was of that school, and having 

 laid a foundation in a chapter entitled, 'Mechanical propositions 

 useful for the more exact determination of the motive power 

 of muscles,' he treats in succession of the various problems 

 of muscular mechanics, of flexion and extension, and of the 

 more complex problems of standing, walking, running, and 

 other forms of locomotion; he investigates these in the same 

 rigid, exact manner, calling in the aid of mathematical figures 

 and calculations, as he and others had investigated the problems 

 of falling bodies, and of the action of various propulsive and 

 other machines. 



One has only to compare the chapters of Fabricius with 

 those of Borelli which deal with any one of these problems, 

 that of walking for instance, in order to realize what a large 

 bound forward mechanical science had made in the first 

 years of the seventeenth century. 



Borelli's discussions concerning these special problems may 

 be read with profit even at the present day ; they supply the 

 basis of muscular mechanics, and interspersed among them will 

 be found shrewd observations, which pass from mere mechanics 

 into more distinctly physiological questions, such for instance 

 as that in which he calls attention to the distinction between 

 the weak tonic contraction which a muscle may exercise against 

 an antagonist muscle, and the more powerful voluntary con- 

 traction, by which the same muscle does work equivalent to 

 raising a heavy weight. 



Not content with the solution of these problems of muscular 

 mechanics, problems which could be solved by the almost 

 direct application of known mechanical methods, and which 

 called for little special research beyond the mere determination 

 of the necessary data, Borelli passes on to the more general, 

 more distinctly physiological, far more difficult question of the 

 nature of muscular movement ; this also he attempts to solve 

 by the mechanical mathematical method. 



It was recognized of old that the movements of the limbs 

 and of the various parts of the body were brought about by the 

 shortening of the structures called muscles. It was also 



