794. KEPORT — 1894. 



cochlea. Professor M'Kendrick stated that the Royal Society had enabled him to 

 continue the investigation, and that a more refined apparatus was in course of 

 construction. 



5. On some Physiological Aj^plications of the Phonograph. By John G. 

 M'Kendrick, M.D., F.R.S., Professor of Physiology in tlue University 

 of Glasgoiv. 



Professor M'Kendrick exhibited one of the newest forms of the phonographs of 

 the Edison-Bell Corporation, and by the aid of a large resonator adapted to it by 

 himself he was able to cause the instrument to speak so loudly as to be distinctly 

 heard throughout the large room in which the Section met. He e'splained the 

 mechanism of the instrument, and showed how it might be adapted for recording 

 the voices of two persons at one time, and for transmission of speech to a distance, 

 by using along with it a microphone in a telephonic circuit. He also described 

 attempts he had made to register the voice curves by means of a small and light 

 lever running along the grooves and recording on a small smoked cylinder travelling 

 at a slow rate, and he exhibited curves obtained in this way. His method was 

 quite different from that employed by Professor Hermann, of Konigsberg. These 

 curves showed long undulations, at periods of about one second, with the speech 

 curves superposed on these. He also explained methods by which the phonograph 

 might be used for recording respiratory and cardiac sounds, and he stated that, 

 whilst he had been as yet unable to record cardiac sounds, he had obtained several 

 respiratory curves, and also the sound of the ticking of a watch. He announced 

 ills intention of continuing the investigation with more delicate apparatus. 



G. On Trophic Changes in the Nervous System. 

 By Justus Gaule, Professor of Physiology, University of Zurich. 



The author has been able by experiments upon the inferior cervical ganglion of 

 the sympathetic to bring about changes in different organs, especially in the biceps 

 and psoas muscles. As the result of further research, he is able to follow out the 

 trophic efiect from the spot where the operation is performed up to the organ 

 ■which subsequently undergoes change. The pathway of this trophic effect passes 

 through the spinal cord ; the author in previous communications had already pointed 

 this out as the probable pathway, and now this supposition has been confirmed by 

 microscopical examination. It has been found that the path is marked out by 

 •changes of a trophic nature in the nervous system, passing from the point of section 

 to the organ which undergoes change. It was necessary in order to remove any 

 doubt to perform the experiment in such a way that the injury caused by the 

 operation could have little or no part in bringing about the changes in the nervous 

 system. 



At last it was found that the trophic changes took place throughout the whole 

 length down to the biceps or psoas muscles when a special nerve scarcely visible 

 to the naked eye was cut awa}^ with scissors from its ganglion. This nerve joins 

 the ganglion near the spot where one of the accelerator nerves arises. When the 

 •operation is peribrmed in this way the injury is so slight that if the section does 

 not involve the right part of the nerve there are practically no after-effects to be 

 observed in the animal. We must therefore attribute to a special trophic influence 

 those changes which can be observed after the section of the nerve has been 

 properly performed. The changes can be classified according to the different 

 parts of the trophic path in which they lie: — 



Those of (1) the sympathetic ganglion ; (2) the rami communicantes ; (3) the 

 spinal ganglia and posterior roots; (4) the spinal cord; (5) the anterior roots and 

 nerve-trunks; (G) the smaller divisions of the nerves in muscle; (7) the nerve- 

 endings in muscle ; (8) and lastly those of the muscle itself. 



