CIRCULA TION. 501 



Portal System. It has already been said that vaso-constrictor fibres for the 

 portal vein were discovered by Mall * in the splanchnic nerve. Constrictor fibres 

 have been found by Bayliss and Starling 2 in the nerve-roots from the third to 

 the eleventh dorsal inclusive. Most of the constrictor nerves pass out from 

 the fifth to the ninth dorsal. 



Back. The dorsal branches of the lumbar and intercostal arteries, issuing 

 from the dorsal muscles to supply the skin of the back, 3 can be seen to con- 

 tract when the gray ramus of the corresponding sympathetic ganglia are 

 stimulated. 



Limbs* The vaso-motor nerves of the limbs in the dog leave the spinal 

 cord from the second dorsal to the third lumbar nerves. 5 The area for the hind 

 limb, according to Bayliss and Bradford, 6 is less extensive than that for the 

 fore limb, the former receiving constrictor fibres from nine roots, namely the 

 third to the eleventh dorsal, the latter from six roots, the eleventh dorsal to 

 third lumbar. Langley 7 finds that the sympathetic constrictor and dilator 

 fibres for the fore foot are connected with nerve-cells in the ganglion stella- 

 tum ; while those for the hind foot are connected with nerve-cells in the sixth 

 and seventh lumbar, and the first, and possibly the second, sacral ganglia. 



Tail. 8 Stimulation of any part of the sympathetic from about the third 

 lumbar ganglion downward almost completely stops the flow of blood from 

 wounds in the tail. The vaso-motor fibres for the tail leave the cord chiefly 

 in the third and fourth lumbar nerves. Their stimulation may cause primary 

 dilatation followed by constriction. 



Muscles. 9 According to Gaskell, 10 the section of the nerve belonging to 

 any particular muscle or group of muscles causes a temporary increase in the 

 amount of blood which flows from the muscle vein. The stimulation of the 

 peripheral end of the nerve also increases the rate of flow through the muscle. 

 The same increase is seen on stimulation of the nerve when the muscle is kept 

 from contracting by curare, provided the drug is not used in amounts sufficient 

 to paralyze the vaso-dilator nerves. 11 Mechanical stimulation by crimping the 

 peripheral end of the nerve gives also an increase. 12 The existence of vaso- 

 dilator nerves to muscles must therefore be conceded. The presence of vaso-con- 

 strictor fibres is shown by the diminution in outflow from the left femoral vein 

 which followed Gaskell's stimulation of the peripheral end of the abdominal 

 sympathetic in a thoroughly curarized dog, 13 but the supply of constrictor fibres 



1 Mall, 1890, p. 57 ; 1892, p. 409. ' Bayliss and Starling, 1895, p. 125. 



3 Langley, 1895, p. 314. 



4 Literature : Lewaschew, 1882, p. 389 ; 1884; Laffont, 1882, p. 864; Bowditch and Warren, 

 1886, p. 416; Humilewski, 1886, p. 126; Langley, 1891, p. 375; Jegorow, 1892, p. 69; Pio- 

 trowski, 1892, p. 464; Thompson, 1893, p. 104; Langley, 1893, p. 227; Piotrowski, 1894, p. 

 258 ; Wertheimer, 1894, p. 724 ; Bayliss and Bradford, 1894, p. 16 ; Langley, 1895, p. 307. 



5 Bayliss and Bradford, 1894, p. 22. 



6 Bayliss and Bradford, 1894, pp. 16, 17 ; compare Langley, 1895, p. 307. 



1 Langley, 1891, p. 375. 8 Langley, 1895, p. 311. 



9 Literature: Sadler, 1869, p. 77; Gaskell, 1876, p. 45; 1877, pp. 360, 720; Griitzner and 

 Heidenhain, 1878, p. 1 ; Gaskell, 1878, p. 262. 



10 Gaskell, 1878, p. 262. " Ibid., p. 274. 12 Ibid., p. 275. 1S Ibid., p. 277. 



