PREFACE. 



vii 



I have explained the similarity of muscles and 

 bones in the vertebrate animals on simple Teleo- 

 logical principles, without making use of the un- 

 proved hypothesis of their descent from a supposed 

 common ancestor. 



In the discussion of the Theory of Muscular 

 Types, and of the Laws of Fatigue and Refreshment, 

 I have succeeded in obtaining many new and interest- 

 ing applications of exact science to the problems of 

 Animal Mechanics. 



I take this opportunity of returning my thanks to 

 Dr. Alexander Macalister and to the Rev. Richard 

 Townsend, who have assisted me materially in the 

 Anatomical and Geometrical branches of my subject ; 

 and also, to the Provost and Senior Fellows of Trinity 

 College, Dublin, for the assistance they have given 

 me, by defraying a portion of the expenses of pub- 

 lication. 



SAMUEL HAUG1ITON. 



Trinity College, Dublin, 

 ist January, 1873, 



