ON THE FUNCTIONAL ACTIVITY OF NERVE CELLS. 717 



nervous system, in the hope that the character of the discharge from the 

 efferent nerve cells may be thus elucidated. 



The research has, so far, amply fulfilled the expectations of the authors, 

 and it is particularly gratifying to them to feel that the results are not 

 dependent upon the possession of a particular capillary electrometer. 

 This is shown by the circumstance that when, owing to an unfortunate 

 accident, the instrument was broken, a second one, made for the purpose, 

 has given, if anything, better results than that originally employed. It 

 appears, therefore, that any electrometer of adequate sensitiveness and 

 sufficient rapidity will furnish records of the change, if appropriately used. 

 Since every delicate capillary electrometer is, from the nature of things, a 

 perishable instrument, this fact is one of great importance for the prosecu- 

 tion of the present research. 



III. The Effects iipon Blood-pressure produced hy the Intra-venous Injection 

 of Fluids containing Choline, Neurine, and Allied Substances. By 

 r. W. MoTT, AI.D., F.R.S., and W. D. Halliburton, M.D., F.R.S. 



In the communication on this subject published in the British Associa- 

 tion Report last year we stated that cerebro-spinal fluid removed from 

 cases of brain atrophy (particularly from cases of general paralysis of 

 the insane) produces a fall of blood-pressure. From the similar result 

 produced by choline we thought it possible that the toxic material 

 derived from the disintegration of nervous tissues, and contained in the 

 cerebro-spinal fluid, was choline also. We have now completed our 

 chemical examination of the material, and proved that our supposition is 

 correct. 



The fall of blood-pressure which occurs is partly of cardiac origin, but 

 its main cause is vascular dilatation in the splanchnic area. This was. 

 investigated by the use of Barnard's cardiometer, and by the use of 

 air-plethysmographs applied to various organs. The intestinal oncometer 

 used we owe to the ingenuity of Mr. A. Edmunds, B.Sc, who has 

 described the instrument in the 'Journal of Physiology,' vol. xxii. 1898, 

 p. 380. 



By means of section of the spinal cord, and also by the use of large 

 doses of nicotine, we have cut out the influence of the central nervous 

 system, and of peripheral vaso-motor stations. Choline still produces, 

 under these circumstances, the usual fall of blood-pressure, which is there- 

 fore due to the action of the poison on the neuro- muscular apparatus of 

 the blood-vessels. 



The allied alkaloid, neurine, produces somewhat different results, and 

 is far more toxic. There is a primary fall in artei'ial pressure, mainly of 

 cardiac origin ; the slowing of the heart and deepening of respiration are 

 very marked symptoms. Usually this is followed by a rise of pressure, 

 due to constriction of peripheral blood-vessels. In some cases this latter 

 phase is absent ; and in some few cases, using very small doses, the second 

 phase only occurs. 



IV. On the Myelination of Nerve Fibres. By H. V. Anderson, M.D. 



A systematic investigation of the peripheral nervous system of man, 

 the cat, and the rabbit has been commenced to ascertain the relative 



