104 WONDERS OF ORGANIC LIFE. 



conversation, is spoken with fluency ; circum- 

 stances are related ; conversations are carried on 

 with imaginary beings ; poetry is recited, and, 

 in fact, mental exercises performed by persons, 

 often servants or uneducated individuals, utterly 

 incapable, when awake, of displaying such 

 accomplishments. Dr. Abercrombie adduces a 

 number of most surprising cases, well authen- 

 ticated, some of which came under his own 

 medical treatment. Epilepsy not unfrequently 

 supervenes on this state of nervous derange- 

 ment. Nightmare and somnambulism are, per- 

 haps, only phases of the same disease, or may 

 be associated together. 



During sleep, the pulse and respiration 

 become naturally slower than during the 

 hours of activity, and the nervous energy 

 and temperature of the body are diminished. 

 Quadrupeds and birds assume such positions 

 as tend to prevent any great decrease of animal 

 heat. Animals crouch, fold their limbs, or 

 double up the body, and those of gregarious 

 habits nestle together, and crowd into a mass. 

 Birds puff out their plumage, and shroud the 

 head beneath the wing. To these rules the re 

 are exce'ptions; for some quadrupeds, as the 

 horse, as often sleep standing as lying down ; 

 and some birds sleep standing on one \eg f curi- 

 ously balancing themselves — a proof that, how- 

 ever profound sleep may be, the muscular sense 

 remains unaffected, the sensibility to the posi- 

 tion of the limbs remaining undiminished. 

 This fact is, indeed, one of the many proofs 



