140 Professor J. S. Burdon-Sanderson [May 13, 



higher powers. The microscopical drawings which were thrown on 

 the screen showed that each of the fine membranes which had been 

 described consists of two different structures. Its uj^per surface 

 presents a layer of apparent homogeneous material in which nuclei 

 are distributed at intervals. This may be called the protoplasmic 

 lamina. The under or ventral layer might be called the nerve 

 lamina, for it is made up of the arborisations of the innumerable 

 nervous filaments which spread themselves over the protoplasmic 

 lamina on its under surface. As these filaments branch repeatedly 

 as they approach their destination, their ultimate endings are among 

 the smallest objects which can be distinguished under the microscope. 



The electrical organ offers to the physiologist one of the most 

 striking examples of that adaptation of structure to function which is 

 universal among living beings. A single column of the organ of 

 torpedo resembles in a very remarkable degree a voltaic pile, of 

 which the plates are the elements, but it is a resemblance with a 

 difference. The difference lies in this, that the organ is only a 

 battery when it is waked into activity by a stimulus. This waking 

 up or (to use the ordinary language of physiology) excitation, is 

 derived from the animal's brain, which for the purpose has added to 

 it a special electric lobe on each side, from which the enormous 

 nerves, which are so richly supplied to the electrical organ, emanate. 

 The use of this lobe is obviously not to produce electricity itself, 

 but, at the will of the animal to set free the energy of the organ, i. e. 

 of each of the many thousand plates of which it consists. Thus, of 

 the two laminae of each plate, the nervous and the protoplasmic, each 

 represents a distinct function, the protoplasmic that of producing the 

 required electromotive effect, the nervous, that of receiving from the 

 brain and communicating to the protoplasm the impulse by which it 

 is discharged. 



In a former lecture it had been shown that all the ordinary 

 physiological changes which occur at every moment of our existence 

 in what Bichat called the organs of animal life, particularly in our 

 nerves and muscles, are accompanied by electrical changes, and that 

 although it is not yet possible to give any physical explanation of 

 these changes, rapid progress is now being made in determining the 

 laws of their association with the other physical concomitants of 

 muscular and nervous action. As it is practically much more 

 important to understand the physiology of muscle and nerve than 

 that of the electrical organs of a few fish, the latter has been com- • 

 paratively insufficiently studied. The purpose of the experiments 

 made at Arcachon is to bring the phenomena of the electrical 

 discharge or shock of torpedo and the physiology of its organ, into 

 line with the already very accurately investigated phenomena of 

 nerve and muscle. With reference to these last, certain very definite 

 laws have been established, of which, perhaps, the most fundamental 

 is that when functionally at rest, these structures exhibit no electro- 

 motive action. The structure must have been p-eiiously acted upon 



