248 On the Torpidity of Monkeys and other Animals. 



from its place, and it soon fell asleep again. Other cxperl* 

 ments awoke it again some days atterwards, and it returned 

 for the fourth time to its lethargic state in about 24 hours. 



I have said that more than once I saw unequivocal signs 

 of a very slow respiration, I was anxious to ascertain by 

 experiments and repeated observations if this rtspiration was 

 regularly periodical. Consequently, on tile 4th ot" Ftbruary, 

 at nine o'clock in the evening, I placed tlie snjallest monkey 

 under a b^ll-glass, the edges of .which were in some very 

 clear lime-water. In the midst of the bell-glass was a pe- 

 destal, on which was a concave piece of wood wdiere the. 

 monkey lay as in a nest. 1 took care that the water was 

 exactly of a level within and without the bell-glass at the 

 moment of immersion ; and on the 5th of February, at nine 

 o'clock in the morning, I found that it had risen al)out threq 

 lines in the inside of the bell-glass, and that a pellicle was 

 formed at its surface. It now remained to examine the 

 state of the air contained under the bell-glass, and the na- 

 ture of the pellicle. 



1 tried the air with Volta's celebrated eudiometer, and I 

 found that it had lost a part of its oxygen ; some drops of 

 nitric acid, poured upon the pellicle* produced a very brisk 

 effervescence and liberating carbonic acid. These two ex- 

 periments convinced me that during the lethargic sleep 

 respiration is not suspended : whence it may be presumed 

 that circulation also continues, but with a languor propor- 

 tioned to that of the respiration. I have since been con- 

 vinced of this by examining with a good microscope the 

 wings of bats in the lethargic s(^ate ; and I shall have occa- 

 sion to speak of thiS'in a subsequent menioir, 



The smallest of the two monkeys in my experiment 5 

 continuing in the most profound lethargy, I fixed my cye§ 

 ppon it, and examining it with attention, I perceived a very 

 feeble alternate depression and rising in its flanks. I took 

 jny watch, and I ascertained that these unequivocal signs of 

 respiration were renewed at intervals of four minutes or four 

 minutes and a half, and that there were 14 iii an hour j 

 jind whereas when perfectly awake there were about 1500. 

 ^uch is the law to which these animals are subject in one 



