85 



The Key. Samuel Haughton, M. D., Fellow of Trinity College, 

 Dublin, read the following paper : — 



Notes on Animal Mechanics, 



No. IV. — On the Muscular Anatomy of the Lion. 



During the month of January last a fine Lion died of fever in the 

 Zoological Gardens of this city, which had lived there for upwards of 

 twelve years. I purchased his body for the use of the Anatomical 

 School of Trinity College, in which the dissections were made which 

 are used in this paper. I am indebted to Mr. Little, Medical Scholar 

 of Trinity College, for the drawings from which two of the woodcuts 

 were copied. The animal was in fine condition ; both fat and muscle 

 being well developed, which was to be expected, as he died after a short 

 illness, which commenced on the 27th of December, 1863, and terminated 

 fatally on the morning of the 12th of January, 1864. The Lion died of 

 fever, and his chance of recovery was destroyed by the occurrence of 

 three days' frost during his illness. We had no means of protecting 

 him from the cold, and from the still more deadly damp that followed 

 it during the thaw ; and notwithstanding that he rallied for one day, 

 under the influence of stimulants, he ultimately succumbed to the dis- 

 ease, and died with all the symptoms of a human being in fever. The 

 only pathological appearances found after death were — a small circum- 

 scribed patch of consolidation in the right lung, and traces of chronic 

 rheumatic arthritis in the right shoulder joint. 



Part I. — Muscles of the Hip and Knee Joints. 



1. M. biceps femoris weighs 27} oz. 



This muscle is shown in Fig. 13, and forms a massive triangular 

 sheet, having for its origin the highest point of the tuber ischii; and is 

 inserted by strong fascia continuously from the middle of the femur 

 covering the vastus externus t down the entire length of the outer side of 

 the leg, as far as the tendo Achillis, round which it is fastened. The 

 total length of the muscular fibres from tuber ischii to tenao Achillis is 

 22j inches, and from tuber ischii to highest insertion on femur 8 j 

 inches ; and when the leg is extended, the third side of the muscular 

 triangle is 1 7 \ inches. If the whole sheet of muscle be supposed of 

 uniform thickness (which was nearly the case), the simultaneous contrac- 

 tion of all its fibres will draw the base of the muscular triangle towards 

 its origin, parallel to itself ; and the resultant of all the forces will lie 

 in the bisector of the vertical angle. This resultant must therefore 

 divide the base in the proportion of 22^ to 8 J inches. On making the 

 calculation, it is found that the resultant intersects the base at a point 

 12*38 inches above the tendo Achillis. This point corresponds with the 

 knee joint, and the effect of the whole muscle is the same as that of a 

 single linear muscle from the tuber ischii to the top of the fibula. 



