894 THE NERVES. 



Differential Characters in the Great Sympathetic of the other Animals. 



In all the domesticated Mammals, the general disposition of the great sympathetic is very 

 similar ; so that there are but few and slight differences to note. 



In the Ox, the cervical filament of the sympathetic does not arise from the lower extremity 

 of the superior ganglion, but behind, from its middle portion ; it is divisible into two or three 

 filaments for a certain distance, after which it lies beside the pneumogastrio. The ramuscule 

 that leaves the lower end of the cervical ganglion is very large, and reaches the division of the 

 common carotid ; that which accompanies the iuternal carotid artery is also of considerable 

 size. (Kuminants have 13 thoracic and 6 lumbar ganglia.) 



In tlie Dog, the cervical sym[)athetic cord is closely united with the pneumogastric, and 

 it is not possible to separate them from each other, as can be done in Solipeds and Kuminants. 

 (In the Carnivora, there are 13 thoracic and 7 lumbar ganglia.) 



In the Rabbit, there are two cords which are independent along the whole length of the 

 neck. 



The Pig has a superior cervical ganglion, which is fusiform and very long ; at its lower 

 extremity it gives oli" several filaments, one of which lies beside the pneumogastric in the 

 cervical region, but separates from it to join tlie middle cervical ganglion ; the others pass to 

 the tenth nerve, and are confounded with it at the ganglionic enlargement it shows behind 

 the pharynx. At the entrance to the chest, a branch separates from the pneumogastric, passes 

 along with tlie axillary arteries, and finally enters the lieart. This brancli is perhaps formed 

 by the filaments of the sympathetic that joined the pneumogastric at the upper part of the 

 neck. (The inferior cervical ganglion, according to Leyh, is completely isolated from the 

 thoracic ganglion. The Pig has 14 thoracic and 7 lumbar ganglia.) 



In the other domestic animals other than Solipeds, the number of ganglia in the dorsal, 

 lumbar, and sacral portions depends upon the number of vertebrae in these several regions in 

 the different species. In them, the first subdorsal ganglion is more voluminous and detached 

 than in the Horse. 



Comparison of the Great Sympathetic in Man with that of Animals. 



It is divided and disposed as in animals. The cervical portion is composed of a superioi 

 fusiform ganglion, from which emerge many branches that have been studied with the greatest 

 care. Tliere are described: 1. Superior or intercranial branches. 2. External or anastomosing 

 branches with the first four spinal nerves. 3. Internal or visceral branches, which mix witli 

 the pharyngeal and laryngeal filaments of the pneumogastric. 4. Anterior or external 

 carotideal branches, which pass to the common carotid and the middle of a small ganglion, 

 the intercarotid. 5. Posterior, muscular, or osseous branches. All these are present in the 

 Horse. A cervical filament and two inferior ganglia— middle and inferior— complete this 

 region, of which there is nothing more to be said. 



The thoracic portion is absolutely identical in its disposition with that of animals ; it gives 

 rise to a great splanchnic nerve, and terminates in the semilunar ganglia. 



There are no diflferences to note in the lumbar and sacral portims, which we have described 

 as the pelvic. 



CHAPTEK IV. 



THE NERVOUS SYSTEM IN BIRDS. 



Pkotective Parts of the Cerebro-spinal Axis.— The protective parts of 

 tlie nerve-centres are the same in all vertebrate animals ; consequently, there 



works of his predecessors, and makes known the new results he has obtained in associating 

 anatomy with physiology, summing them up in the following principal conclusions: 1. The 

 vessels receive their nerves from the free filaments of the sympathetic, and trom filaments of 

 the same kind contained in the mixed spinal nerves obtained by the latter from tlie spinal cord 

 and the ganglia. 2. The superficial and deep vessels of the face are nmervated by the free 

 sympathetic filaments from the superior cervical ganglion and the pre-vertebral cord, and by the 

 branches of the facial and the trigeminus. 3. The vessels of the ear receive their nerves from 

 the free sympathetic, the facial, and the trigeminus, as well as the cervical plexus. 4. The 

 encephalic vessels are innervated by the carotid and vertebral plexuses. 



