TIIK (IRKA T s Y V/M 7 7//.T/r XERVOUS SYSTEM. 781 



The terminal branch of the sacral plexus forma the f)rit sciatic nerve, whose 



distribution i.s ihe same ns that of Carnivore. The collateral ramnscnles of the great 



are the brunch of the long portion of the biceps; the semitt ndinosus and 



mbranosus branch; the branch to the great adductor; nnd. Lmtly, tliat to the 



liortion of the biceps. It terminates by the extermd and iiit.-ninl j>o|".liteul. 



The nitttculo-cutaneou* and anterior tibial, continuations of th external poplitens, 

 comport themselves almost the same as in the Dog. They form dorsal collaterals to the 

 third, fourth, and fifth toes, as well ns to the second. 



The hit?rnul }H>jilitt>al presents an external saphenons nerve that passes along the 

 externnl border of the foot, and has, in addition, a branch that ascends on the dorsum 

 of that org;m. The external saphenous furnishes the di)rsal collaterals to the first toe, 

 and the external collateral to the second. The porterior tibial nerve continues the 

 internal sciatic in the leg ; it terminates in the plantar nerves. The intern.il plantar 

 furnishes the collateral nerves to the fifth, fourth, and third toes, and the internal 

 collateral of the second toe. The external divides into three branches : the two 

 Miperlk-iid branches form the collaterals of the first toe, and the external collateral of tlie 

 second; the deep branch passes inwards, behind the interosseous muscles, and is 

 expended in those of the fourth space, after giving filaments to the oblique abductor of 

 the large toe, tiansverse abductor, last two lumbrieales, to tlie interosseous, and very 

 fine filaments to the articulations of the tarsus with the metatarsus. 



It will therefore be seen that, in Man, the branches of the deep trunk of tho 

 external plantar join those of the internal plantar, to form the collateral nerves. 



CHAPTER III. 



THE GREAT SYMPATHETIC NERVOUS SYSTEM. 



PREPARATION" OF THE GREAT SYMPATHETIC. The same subject ought to suffice for the 

 preparation of this, us tcell as the pneumogastric and spinal nerves. After placing the 

 animal in the first position, the intestines are removed, one of the posterior limbs cut 

 otY. and the greater portion of the os innominatum cleared away by sawing through the 

 symphysis pubis and the neck of the ilium ; the dissection of all the alxlomino-pelvic 

 portion of the system, ami that of tlie terminal branches of the pneumogastric nerve, is 

 then proceeded w.th. The anterior Lmb of the same side should be afterwards 

 detached, the scapula having been previously MI\\H across its middle part, and tlm 

 thorax thrown o|>en by the ablation of the entire costal wall, in sawing through tho 

 eternal cartilages below, and the ribs aliove, at their superior extremity All tho 

 thoracic portion of the ganglionic nervous apparatus, and the pneumogasirii- n. i\. - 

 may then be prepared. Nothing more remain.-- to be accomplished except the dissection 

 of the sympathetic and the vngus nerve in the cervico-eephalic region, with that of the 

 spinal nerve; this operation is not attended with any difficulty, and should be precrd.-d 

 by the extirpation of a branch of the inferior maxilla. It is useful to inject th>- arti-ri.-i 

 previously; as then the filaments of the s>ym|>utht tie that lie alongside the v .-- I 

 of the different organs in the abdominal c.iv.ty can be more easily followed. 



The great ffmpatiutie, also named tbe triplanchnic system 

 an intestine or viscus), because of its position and destination, is the nervous 

 apparatus of the organs of vegetative life. 



As has been already shown in the general consideration of the nerves 

 and the whole nervous system, this apparatus has for its base two long cords 

 extending from the head to the tail, underneath tho vertebral column, and to 

 the right and left of the median line. Towards the last sacrul vertebra, a 

 portion of these two cords converge towards each otlu r, ami lie beside the 

 in. Imn coccygeal artery. Some anatomists think that the great sympa- 

 thetic does not stop at this point, but is praloogod beneath tho coccygeal 

 vertebrae, where it enters a ganglion that has !><:. <1 of late years 



as the "coccygeal gland," and whoso nature has been very much contestl. 



Each cord presents on its course numerous _':t;i'.'lia. t<> whose JM-. sriuv it 



