ANATOMY AND PHYSIOLOGY OF NERVOUS SYSTEM. 681 



destroyed. G-oltz and Freusburg have observed in a bitch, whose 

 spinal cord was cut at the level of the last lumbar vertebra, the mani- 

 festations of desire, conception, gestation, delivery, and lactation to 

 take place just as in a sound bitch. 



In obstetrical wards women are delivered while in the anaes- 

 thetic sleep produced by ether, chloroform, or other anaesthetics. 



These various facts show that the center of the movements of 

 the uterus is found in the spinal cord, and not in the brain. 



The sudorific centers are seated in the spinal cord. The spinal 

 cord has minor vasomotor centers for the vessels of the parts it inner- 

 vates. In fact, cutting the cord produces hypersemia and eleva- 

 ion of temperature in the paralyzed parts. This is due to the 

 ralysis of the vessels there. The constrictors are paralyzed. 



Electrical excitation of the peripheral stump lowers the tem- 

 perature in the parts innervated, by constricting the lumen of the 

 corresponding arterioles. The vasomotor fibers, emanating from the 

 spinal column, rejoin the vessels either directly, or, more commonly, 

 y means of branches of the sympathetic. 



The cilio-spinal center is seated in the medulla oblongata and 

 ds fibers down the dorsal cord to the third dorsal vertebra. These 

 fibers emerge by the anterior root of the two lower cervical and the 

 two upper dorsal nerves and go into the cervical sympathetic to the 

 dilating fibers of the iris. Pinching the skin of the neck will dilate 



Ie pupils : another skin reflex. 

 Physiology of the Medulla and its Nerves. 

 The medulla oblongata, or bulb, like the spinal cord, is an organ 

 01 transmission, or conduction, but at the same time it is a center of 

 ,rticular and very important functions. 



Double Conduction, Like the spinal cord, the medulla carries 

 ntripetal, or sensory actions, and centrifugal, or motor actions, 

 he former are conveyed by means of its posterior part; the latter 

 y the anterior part. 



The centripetal, sensory conduction is crossed or decussated 

 ong the floor of the fourth ventricle. The centrifugal, motor 

 nduction accomplishes, instead, its decussation in the pyramids of 

 e medulla, where the right, lateral fibers pass to the left, and vice 

 This decussation of the fibers is much more complete in 

 an than in animals. So much is this so that in man a lesion 

 hich destroys one-half of the medulla brings on complete hemi- 

 legia of the opposite side; in animals a similar lesion never pro- 



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