766 



HIBERNATION. 



causes ; and it is equally manifested in its pe- 

 culiar effects, only varying in degree and inten- 

 sity. 



In giving a distinct idea of hibernation we 

 must extend our views to the altered condition 

 of each function in the animal economy, for 

 this peculiar state is not limited to any special 

 function or organ. It is, in fact, a treatise on 

 physiology which should be written, compa- 

 ring the state of each function and of each 

 organ, in the hibernant or lethargic and in the 

 active condition, a disquisition on sleep, indeed, 

 in its various degrees, and in its effects in mo- 

 difying the various functions. 



The first question then is, what is sleep 1 a 

 question difficult, perhaps impossible, to an- 

 swer, if we mean by it what is its nature or 

 essence, but highly interesting to prosecute, if 

 we mean what are its special phenomena and 

 their mutual relations. 



In order to treat of sleep properly, I must 

 first observe that, of the nervous system, of 

 which it is primarily a modification, formerly 

 divided into the cerebro-spinal and the ganglio- 

 nic, the first division must now be subdivided 

 into the cerebral and the true spinal, the former 

 being the exclusive seat of sensation, volition, 

 &c. ; the latter, the special source of certain 

 actions now designated excito-motory, and ob- 

 served in the orifices, the ingestors, the expul- 

 sors, the sphincters, &c. Now it is the cere- 

 bral system which sleeps, the true spinal re- 

 taining all its energies. 



From this enunciation of the primary fact in 

 sleep, we may trace the whole of the pheno- 

 mena of this singular condition. In the state 

 of activity, the cerebral system exerts a peculiar 

 and continual influence over the true spinal, 

 which ceases during sleep. In this manner the 

 functions of the latter appear impaired ; the re- 

 spiration especially, and with the respiration 

 the circulation, with which it always maintains 

 a certain relation, becomes slower, irregular, 

 and suspended at intervals. These phenomena 

 observable in ordinary sleep are still more re- 

 markable in the deep sleep or lethargy of 

 hibernation or diurnation. 



In order that the effects of hibernation may 

 be traced in relation to all the functions of the 

 animal economy, I must enter into a few brief 

 details relative to the arrangement of these 

 functions and the order in which I propose to 

 notice them. The most simple and natural 

 arrangement of the functions appears to me to 

 be the following : 



I. SANGUIFICATION. 



1. The ingestion and) cc , 



2. The digestion.... 5 f f d - 



3. The formation.... I ;^^ e - 



4. Absorption \.f ^y the lacteals. 



( 6. by imbibition. 



5. The organization of the blood. 



II. RESPIRATION. 



1. The absorption .. \ a ' ox yg en - 



{b. of nitrogen, &c. 



2. The exhalation . . \f j> rbonic f^- 



( b. of nitrogen, &c. 



3. The results 



a. augmented temperature. 



b. a direct ratio between the 

 pulsations and respirations. 



c. an inverse ratio between 

 the respiration and irrita- 

 bility. 



III. THE CIRCULATION. 



1. The pulmonic. 



2. The systemic. 



3. The cardiac or coronary. 



4. The hepatic. 



5. The splenic. 



6. The circulation as the ( a. of nutrition. 



carrier {b. of temperature. 



IV. DEFCECATION. 



1. Re-absorption by the lymphatics. 



f a. by the lungs. 

 ^ b. by the skin. 



2. Excretion s c . by the liver. 



i d. by the kidneys. 

 v e,. by the intestines. 



V. THE NERVOUS SYSTEM. 



1 . The cerebrai, or the system of 



a. The sensations, the senses. 



b. Volition, spontaneous motion. 



2. The true spinal or excito-motory, or the 



system of 



a. The orifices. 



b. Ingestion. 



c. Expulsion. 



d. The sphincters. 



3. The ganglionic. 



VI. THE MUSCULAR SYSTEM. 



1 . The irritability. 



2. The motility. 



I proceed to trace the influence of sleep, and 

 of the deeper sleep of hibernation upon these 

 various functions, beginning with the former. 



I. Of sleep. It was first ascertained experi- 

 mentally by Messrs. Allen and Pepys, that the 

 quantity of respiration is diminished in ordinary 

 sleep.* The acts of respiration are obviously 

 less frequent and less regular, being frequently 

 suspended for a moment and renewed by a deep 

 inspiration. The animal frame becomes more 

 susceptible of the influence of cold. It is most 

 probable that, during this condition, the irrita- 

 bility of the muscular system is augmented, 

 and that this is one of ihejinal objects of sleep; 

 experiments, however, are still wanting to 

 establish a fact in reference to ordinary sleep, 

 which is clearly proved in regard to the sleep 

 of hibernating animals, and the deeper sleep or 

 lethargy of hibernation, I shall now proceed 

 to treat of the sleep of hibernating animals. 



II. Of the sleep of hibernating animals. In 

 the sleep of the hibernating animal, the respira- 

 tion is more or less impaired : if the animal be 

 placed in circumstances which best admit of 

 observation, the acts of respiration will be 

 found to have greatly diminished ; if it be 

 placed in the pneumatometer, little alteration is 



* Phil. Trans, for 1809. 



