ANIMAL MECHANICS. 



and other joints of many animals, and that I have never met 

 with any exception to the following Propositions, which may 

 be regarded as summing up my results : — 



i°. Each muscle is constructed in relation to its joint, in such 

 a manner as to perform one kind of work, only ; and it performs 

 that work to maximum advantage. 



2°. The number of muscles employed is determined by the 

 number of distinct actions required from the limb. 



3°. The shape and form of the bones employed are the 

 necessary consequence of the shape and power of the muscles in 

 action. 



4°. The smallest muscle in the combination is as carefully 

 adapted to its conditions of maximum work as the largest muscle. 



From these Propositions, supposed to be extended to the 

 action of every muscle and joint, it appears to me to follow 

 as necessary consequences : — 



i°. That a foreseeing Mind planned the type of the limb, 

 and of its actions. 



2°. The idea of the limb and of its necessary actions being 

 given; the number, shape, and arrangement of the necessary 

 muscles can be calculated and predicted with as much certainty 

 as an astronomer can predict an eclipse. 



3°. That the shape and arrangement of the bones follow of 

 necessity, from the necessary arrangement of the muscles. 



4°. That any alteration, however slight, in any 'part of the 

 combination of bones, muscles, and joints, would entail a loss of 

 work, and lead to a less perfect mechanism, 



5°. Hence, the permanence and stability of each species {so 

 far as relates to bones, muscles, and joints) is absolutely secured, 

 on the principles so admirably laid down by Mr. Darwin. 



6. The profound study of the mechanism of joints lends no 

 support to the postulate, that the similarities found to exist in the 

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