TRANSACTIONS OF THE SECTIONS. 151 



eleventh lumbo-caudal vertebra. Posterior to this point, therefore, we have arrsinged 

 around the vertebral column four great nervous cords — two of which are superior, 

 and situated one on each side of the A'ertebral spines, and two inferior, and placed 

 one on each side of the vertebral bodies below tne transverse processes. They are 

 continued back to the tail, and their chief function is to supply the four great 

 muscles which act on the tail. Sensory filaments, however, are also given to the 

 fekin. 



The first eleven of the inferior divisions of the lumbo-caudal nerves do not enter 

 into the formation of the great inlVrior cord. They correspond to the lumbar and 

 sacral nerves in man. The large internal pudic nerve takes origin from the more 

 posterior of these. 



liecent additional Ohservations on the Physiohf/ical Action of SI'jht. 

 By Prof. Dewar, F.E.S.K 



On the Action of Vanadium upon the Intrinsic Nervous Meclianism of the 

 Frog's Heart. By Prof. Aethuk Gamgee, F.R.S., and Leopold Laemuth. 



Method of Experiment.— \ frog's heart was ai-ranged with an artificial circula- 

 tion, the blood (i. e. rabbit's seruni) passing from a reservoir of given height through 

 the auricles, ventricle, and bulhus aurice, and being allowed to trickle back into the 

 reservoir down the sides of a glass rod, so as to be exposed iu a thin him to the air. 

 In the course of this artificial circulation a mercurial hsemodynamometer was inter- 

 posed, arranged so as to record its movements on a blackened cylinder. Before 

 taking a tracing the outlet of the blood from the circulating system back into the 

 reservoir was obstructed, thus causing the mercury in the distal manometric limb 

 to rise and oscillate. Normal tracings were first taken ; then the serum was 

 mixed with a solution of a sodium salt of vanadium (NaVOj, or Na^V.^O., or Xa, 

 VO4), and other tracings taken at intervals. When the effects of vanadium-poison- 

 ing were well advanced the vagus nerve was stimulated in certain cases and the 

 eflects noted. In other cases atropin-poisoning was induced prior to mixing the 

 serum with the salt of vanadic acid. 



Besidts of Experiments. — "When vanadized serum flows through a beating frog's 

 heart (being present iu a proportion of -098 per cent, of V.^Oj the force of ventri- 

 cular systole is much diminished, the ventricle passes into persistent contraction 

 for a time, while the auricles pulsate as usual or somewhat enfeebled. If the pro- 

 portion of vanadium were twice as large, the ventricle stops writhing one or two 

 minutes in a state of rigid contraction, in which it continues for a long time, often, 

 however, relaxing again before death. 



When so contracted, excitation of vagus, sufficient to stop the auricles, has no 

 effect on the ventricle. 



The previous administration of atropia does not iu the slightest modify the above 

 results. 



On the Difference in the Poisonous Activity of Phos2)horus in Ortho-, Meta~, and 

 Pyrophosphoric Acids. By Prof. Arthur Gamgee, F.E.S., John PRiESTLEi', 

 and Leopold Larmuxh. 



In their experiments the authors made use of frogs, rabbits, and dogs ; and the 

 sodium salts of the phosphorus acids investigated were introduced into the system 

 either subcutaneously or by venous injection. The salts used were trisodic ortho- 

 phosphate, tetrasodic pyrophosphate, and sodic metaphosphate, the standard solu- 

 •tions being made to contain the same amount of phosphorus calculated as P.fly 



As the result of then' experiments the authors state ; — 



1. That trisodic orthophosphate is physiologically inactive. 



2. That sodic metaphosphate is a poisonous substance, but not so poisonous as 

 pyrophosphate of sodium. 



