CONTRACTILITY OF VISCERA 



by Oliver and Schafer in 1894 {Jnl. of 

 Fhysiol. vols, xvi, p. i ; xvii, p. ix ; and xviii, 

 p. 230). Its activity is mainly or entirely due 

 to the substance adrenaline first isolated in 

 purity by Jokishi Takaniine (1901, Am. Jnl. 

 of Physiol, and Proc. of Physiol. Dec. 1901, 

 Jnl. of Physiol, vol. xxvii, p. xxix), and 

 synthesized in its racemic optically inactive 

 form by Dakin, 1905 {Proc. Roy. Soc. B. 76, p. 

 494). Synthetic laevo adrenaline has(Cushny, 

 Jnl. of Physiol, xxxvii. 130, 1908 ; xxxviii. 

 259, 1909) the same potencyas natural (laevo) 

 adrenaline, whereas the dextro-rotatory part 

 of the synthetic adrenaline has only one- 

 thirteenth that strength. Langley pointed 

 out, 1901 (Jnl of Physiol xxvii, p. 237), that 

 in practically all points of its action ' adrena- 

 lin ' produces effects like those of stimulation 

 of the sympathetic nerves ; thus in this exer- 

 cise it inhibits the movements and tonus of 

 the muscular coats of the intestine (text-figs. 2 

 and 3), and causes contraction of the muscular 

 coats of the spleen (text-fig. 4) and of almost 

 all arteries (here aorta, text-fig. 5). Compare 



your own tracing of its effect upon the 

 intestinal strip with Bayliss and Starling's 

 fig. {Jnl of Physiol 1899, vol. xxiv, p. 122) 

 of the effect of stimulations of the splanchnic 

 nerve on the intestine in situ. 



With the exsected intestine as reagent 

 Cannon and Hoskins were able to detect 

 adrenalin in a dilution of 1 part in 200 

 millions. An excellent recent paper to 

 consult is Gunn and Underbill, Quart. Jnl. 

 of Experim. Physiol, vol. v, p. 275, July 

 1914. 



If performed with cat's intestine instead 

 of rabbit's, you will probably find the rhythm 

 slower than with the latter, and your record- 

 ing surface should travel very slowly, but 

 the rate of beat is different from different 

 parts of the intestine. The cat's ileum tends 

 to give slow tonic contractions on which the 

 less slow pendular contractions are super- 

 posed (text-fig. 5) ; the rabbit's ileum rarely 

 exhibits the former (Young, Quart. Jnl 

 of Experim. Physiol, vol. v, p. 349, 1915). 

 Rabbit's duodenum beats better. 



EXERCISE II 



KEVIVAL OF BEAT OF THE EXCISED MAMMALIAN HEART; INFLUENCE 



OF TEMPERATURE THEREON 



I. See that the perfusion apparatus (text-fig. 6) is ready for use. One Obs. 5. 

 of the glass reservoirs e, e' should be filled with Ringer-Locke fluid at room tern- ^©^i'^ai of beat 

 perature ; the fluid used is as in exerc. I except that it contains 1 per cent, j^e^rt by coro- 

 glucose in addition to the inorganic salts. See that the clamp on perfusion- nary perfusion, 

 reservoir tube acts freely; also the clamp controlling the tubing from the 

 warm- water pail to the jacket of the perfusion tube. Open the tap of the 

 oxygen cyli nder and slightly adjust it so that oxygen bubbles slowly through 

 the Ringer- Locke fluid in the reservoir. Five or six bubbles in the half- 

 minute is a sufficient stream. 



Make ready a strong thread ligature loosely tied with the first tie of a 

 reef-knot ; this is for slipping round the aorta. Also have ready a packing- 

 needle about 10 cm. long threaded with fine string about 20 cm. long. 



