102 Mr. Carlisle on a Peculiarity 



no less slow in restoring the parts to their former condition ; 

 or, if the restoration is to be effected by antagonist muscles 

 under the same circumstances, then, the flexion and extension of 

 every part of the limbs will correspond, as to time. 



I have not met with any arrangement of blood-vessels ana- 

 logous to those described, except in the carotid artery of the 

 Lion. May not this peculiarity be subservient to the long conti- 

 nued exertion of the muscles of his jaws, whilst holding a 

 powerful animal, such as a Horse or Buffalo, and thus enable 

 him to retain his prey, until it is wearied out by ineffectual 

 struggles ? I believe also, that those animals which chew the 

 cud, have a plexus of arteries in the neck, analogous to the rete 

 mirabile: but this fact has not yet been verified in all the rumi- 

 nating quadrupeds ; and the effect of these arrangements seems 

 rather to operate as sluices to the arteries of the masticating 

 muscles, than directly as the means of retarding the velocity of 

 their fluids. It is however necessary to examine these subjects 

 more accurately.* 



As I have instituted a series of experiments and inquiries, 

 with the hope of elucidating this subject, it would be improper 

 to trouble you, or the Royal Society, with any physiological 

 reasonings until these are completed. 



I have the honour to be, &c. 



Soho Square, ANT. CARLISLE. 



October 28th, 1799. 



* There is a rete mirabile in the genus Bos* and in some of the Cervi which I 

 have seen ; but of these and the other Pecora a fuller description will be given in a 

 future paper. 



