332 PHYSIOLOGY CHAP. 



(6) Previous destruction of the superior cervical ganglion 

 prevents the trophic changes which result from injury of the 

 Gasserian ganglion alone. 



(c) When disturbances appear in the eye after the double 

 operation, they are constantly recovered from. 



(d) Animals from which the Gasserian ganglion alone is removed, 

 and those in which this lesion was preceded by destruction of the 

 superior cervical ganglion present totally dissimilar symptoms in 

 the eye, independent of whether the trophic alterations are present 

 or not. 



Schiff, Mantegazza, Vulpian, studied the after-effects of tran- 

 section of the spinal nerves to the limbs. After dividing the sciatic 

 and crural nerves, Schiff found in the adult dog, cat, and frog that 

 three to six months after the operation the bones of the operated 

 limb were smaller than those of the normal limb. Mantegazza 

 and many others afterwards drew attention to the muscular atrophy 

 which appears after sensory and motor paralysis of the limb. In 

 two to three weeks the muscle fibres begin to atrophy, and after 

 some months or years they are converted into a tissue resembling 

 connective tissue. Loss of excitability goes parallel with the 

 atrophy, and the electrical reaction of degeneration appears. 



Bidder noted that a few weeks after section of the nerves to 

 the salivary glands these become about half the size of the healthy 

 glands on the opposite side. Nelaton emphasised the clinical fact 

 that the testis atrophies after section of the spermatic nerves. 

 On dividing this nerve in animals, sparing the blood-vessels of the 

 spermatic cord and the vas deferens as far as possible, Obolensky 

 saw that the testis dwindled in two to three weeks, and almost dis- 

 appeared after four months. Histological examination showed that 

 the glandular tissue had almost disappeared, and was replaced by 

 connective tissue and fat. When, on the contrary, the spermatic 

 nerves are spared and the vas deferens is divided, there is no 

 apparent change in the testis. 



In Baldi's experiments (1889) in our laboratory, on the effects 

 of section of the afferent or efferent roots in dogs he paid particular 

 attention to the trophic changes in the skin. Clinical observation 

 had already shown that the diseases of motor and sensory nerves 

 are accompanied by alterations in the nutrition, not only of muscle, 

 but of other peripheral tissues as well ; cutaneous ulceration, for 

 instance, is particularly frequent after lesions of the peripheral 

 nerves. In order to investigate the origin of this dystrophy, Baldi 

 operated on a series of dogs, cutting in some the dorsal, in others 

 the ventral, roots, which subserve the sensibility or the motility, 

 respectively, of an entire fore- or hind-limb, on one or both sides. 



The first effect in the limb that has become completely 

 insensitive is neuro-paralytic hyperaemia, shown in the rise of 

 temperature and reddening of the skin. This is very transient, 



