498 AN AMERICAN TEXT-BOOK OF PHYSIOLOGY. 



Intestines. 1 The mesenteric vessels receive vasoconstrictor fibres from the 

 sympathetic chiefly through the splanchnic nerve. 2 The vaso-constrictors of 

 the jejunum, as a rule, begin to be found in the rami of the fifth dorsal nerves ; 

 a little lower down, those for the ileum come off; and still lower down, those 

 for the colon ; none arise below the second lumbar pair. 3 According to Hal- 

 lion and Franck, vaso-dilator fibres are present in the same sympathetic nerves 

 that contain vaso-constrictors.. The dilator fibres are most abundant or most 

 powerful in the rami of the last three dorsal and first two lumbar nerves. 

 There is some evidence of the presence of vaso-dilator fibres in the vagus. 

 The excitation of the vaso-constrictor centres by the blood in asphyxia pro- 

 duces constriction of the abdominal vessels. 4 The vaso-dilator as well as the 

 vaso-constrictor fibres of the splanchnic probably end in the solar and renal 

 plexuses. 5 



Liver. Cavazzani and Manca 6 have recently attempted to show the pres- 

 ence of vaso-motor fibres in the liver. Their method consists in passing warm 

 normal saline solution from a Mariotte's flask at a pressure of 8 to 10 milli- 

 meters Hg through the hepatic branches of the portal vein and measuring 

 the outflow in a unit of time from the ascending vena cava. On stimulating 

 the splanchnic nerve they observed that the outflow was usually diminished 

 though sometimes increased, indicating perhaps that the splanchnics contain 

 both vaso-constrictor and vaso-dilator fibres for the hepatic branches of the 

 portal vein. The vagus appeared to contain vaso-dilator fibres. Further 

 studies are necessary, however, before pronouncing definitely upon these 

 questions. 



Kidney} The vaso-motor nerves of the kidney leave the cord from the 

 sixth dorsal to the second lumbar nerve. 8 In the dog, most of the renal vaso- 

 motor fibres are found in the eleventh, twelfth, and thirteenth dorsal nerves. 9 

 The stimulation of the nerves entering the hilus of the kidney between the 

 artery and vein causes a marked and sudden renal contraction, but the organ 

 soon regains its former volume. 10 Constriction follows also the stimulation of 

 the peripheral end of the cut splanchnic nerve. 11 Bradford has demonstrated 

 renal vaso-dilator fibres for certain nerves by stimulating at the rate of one 

 induction shock per second. For example, the excitation of the thirteenth 

 dorsal nerve with 50 to 5 induction shocks per second gave always a constric- 



I Literature: Cyon and Ludwig, 1866, p. 136; Cohnheim and Roy, 1883, p. 440: Dastre 

 and Moral, 1884, p. 294; Waters, 1885, p. 460; Bradford, 1889, p. 390; Hallion and Franck, 

 1896, p. 478. * Cyon and Ludwig, 1866, p. 136. 



3 Hallion and Franck, 1896, p. 496. 



4 Dastre and Morat, 1884, p. 294; Hallion and Franck, 1896, p. 506. 



5 Langley and Dickinson, 1889, p. 429. 



6 Cavazzani and Manca, 1895, p. 33: see also Pal, 1888, p. 73. 



'Literature: Nicol aides, 1882, p. 28; Cohnheim and Eoy, 1883, p. 345 ; Klemensiewicz, 

 1886, p. 84; Masius, 1888, p. 539; Bradford, 1889, p. 404; Arthaud and Butte, 1890, p. 379; 

 Preobraschensky, 1892; Wertheiraer, 1893, p. 1024; 1894, p. 308; Bayliss and Bradford, 1894, 

 p. 17. 8 Bayliss and Bradford, 1894, p. 17. 9 Bradford, 1889, p. 404. 



10 Cohnheim and Roy, 1883, p. 345; and Bradford, 1889, p. 364. 



II Cohnheim and Roy, 1883, p. 440. 



