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at every moment, must, to produce the maximum effect, pass through 

 ninety degrees at the same moment ; and we find that Nature accepts 

 the consequence. I know no animal in which this law is not carried 

 out, and a corresponding law to which I shall now call attention in the 

 hind-leg. In the hind leg the line 0...sart (Fig. 7) joining the centre of 

 the hip-joint with the tuber ischii, becomes at right angles to the resultant 

 of the biceps femoris muscle, whether triangular or prismatic, at the same 

 moment that the muscles of the calf (g b) become perpendicular to the 

 line (b y) which is drawn through the centre of the ankle-joint. In the 

 case of the hind -leg the arrangement skips a joint. In the fore-arm the 

 shoulder is related in this remarkable manner to the elbow-joint. In 

 the hind-leg the hip-joint is not related to the knee-joint, but to the 

 heel ; and those two angles, which have no necessary relation 

 whatever to each other, made by one group of forces at the hip- 

 joint, and another group of forces quite distinct from them at the heel, 

 pass through ninety degrees together — one of the most remarkable in- 

 stances on record of the skill, contrivance, and foresight, with which 

 the frame of animals has been constructed. 



You have seen on board a large steamship an engineer with a little 

 can of oil in his hand putting his head in among moving bars of iron, 

 poking his can of oil among little joints ; and you feel conscious that if 

 you attempted to do it you would lose your life. That man knows to 

 the tenth of an inch the motion of every bar — when it comes, when it 

 retreats, when it comes forward again ; he knows that he can rely upon 

 the motions of the bars with certainty to the hundredth part of an 

 inch. When we see these motions regulated by the intelligence of the 

 engineer who contrived the machine, describing their angles, and pass- 

 ing through each angle at the exact moment the engineer intended, no 

 person is fool enough to believe that there is not contrivance and de- 

 sign. I am ashamed to say there are intelligent men who can look upon 

 similar structures more wonderful in contrivance in the world of nature, 

 and not recognise the hand of Him who made them. 



Before parting with this subject, I may be allowed to give a word of 

 advice to some of those who hear me. I have shown you that these 

 two angles pass through ninety degrees together ; therefore, any ar- 

 rangement of an artificial kind that interferes with the angles passing 

 through ninety degrees together would be most injurious. I am told 

 that it IS now the habit, or has been the habit, of ladies in America — 

 perhaps in this countiy — to wear high-heeled boots for the purpose of 

 producing the Grecian bend. I am not acquainted with the subject, 

 but the ladies present will know whether this be the fact. I would 

 caution you against the practice. You shorten, by high-heeled boots, the 

 distance between the points b and G ; you prevent, therefore, the beau- 

 tiful play of angles and joints from coming into effect, and you sacrifice 



