586 Analysis of Books, Sfc. 



The canal in which the carotid is lodged in passing through the 

 ear of the hybernants, is in some cases merely membranous, whilst 

 in others it is completely bony, the stapes, in that case, being fixed 

 to the cavity of the tympanum by the bony tube passing through its 

 ring. 



We are not justified in viewing this structure as a cause of hyber- 

 nation. In all these animals, in fact, the tympanum and other 

 parts of the ear are so large, that in connexion with the bulk of the 

 submaxillary and thymus glands of the pterygoid muscles, and the 

 posterior processes of the lower jaw, that the whole of the base of 

 the cranium is occupied, and no other course is left for the passage 

 of the carotid artery than through the tympanum. Besides, these 

 animals, when torpid, are rolled up, with the head buried between 

 the legs ; so that, if the carotid took its ordinary course, it would 

 scarcely fail to be compressed, and the passage of blood through it 

 obstructed. 



On a Peculiar System of Visceral Nerves in Insects, analogous to 

 the Sympathetic. By Dr. J. Mueller. 



AMONGST the numerous questions connected with the study of the 

 sympathetic nerve, none has been more frequently discussed, or 

 more variously decided than that which has for object the determi- 

 nation of the true relations of this nerve, as it exists in the higher 

 classes of animals, and the nervous system at large of the lower 

 classes, including the whole of those without vertebrae. Nor is this 

 one of those minor and comparatively unimportant investigations 

 with which most sciences abound, and of which the results have not 

 any immediate influence on fundamental doctrines. On the con- 

 trary, the various modes in which the same anatomical facts have 

 been viewed by different individuals engaged in this inquiry, have 

 uniformly had a direct reference to the physiology of the most 

 important of the systems of which animals are composed. 



Ackermann, Reil, and Bichat, with numerous followers, misled 

 by superficial examination and imperfect analogy, assumed and 

 reasoned upon a perfect identity of character between the sympathetic 

 nerve of vertebral, and the ganglionic chain of articulated animals ; 

 an assumption on which was raised a superstructure of most im- 

 portant physiological conclusions. 



Scarpa, Blumenbach, Cuvier, Gall, J. F. Meckel, Arsaky, and 

 Carus, trusting less to first impressions, and guided rather by the 

 examination of the natural laws regulating the progressive develop- 

 ment of parts in the animal scale, showed that there existed suffi- 

 cient grounds for rejecting this supposed analogy. Meckel and 

 Von Walther expressed the opinion, that the cords extending from 

 the brain into the body of invertebral animals were to be viewed as 

 .uniting in themselves the characters of the subsequently disjunct 

 -systems (in vertebral animals) of spinal marrow and sympathetic 

 jierve ; inclining, in mo-lusca, to the type of the latter ; in articulata, 

 of the former. Rudolphi has expressed the same idea in a still 



