456 Royal Society : — >■ 



impossible to conceive that the change of form which takes place in 

 a muscle during contraction may be momentarily followed by the 

 inversion of tlie muscular current in the exterior arc. He observes, 

 that examples are not wanting, taken from certain cases of electro- 

 dynamic induction, and also of voltaic circuits, in which this inversion 

 of the current can be obtained by a change in the form, or relative 

 distance of different parts of the circuit ; but he adds, that this is a 

 new field of inquiry, which cannot be given up to merely hypothetical 

 views. 



The last section of the paper is devoted to the consideration of the 

 mechanical effects of muscular contraction ; and experiments are 

 stated with a view to compare the effective work of a muscular con- 

 traction, as determined empirically ^rith the work calculated according 

 to the principles of the dynamical theory of heat. 



Employing the dynamometer already described in the fourth series 

 of his researches, the author has found that the mechanical work 

 effected by a single contraction of the gastrocnemius muscle of a 

 frog may be expressed by 0'00001457 kilogramme-metres. Deter- 

 mining next the quantity of zinc required to be oxidated in the pile 

 in order to excite a single contraction, he finds that the force de- 

 veloped by the muscle is enormously greater than could be accounted 

 for on the supposition that it is produced by the conversion into 

 muscular energy of the equivalent of electricity corresponding to the 

 quantity of zinc oxidated. lie accordingly concludes, that the 

 electric current which excites a muscle to action does not represent 

 the force exerted by the muscle, which is more probably to be 

 referred to the chemical changes, such as oxidation, which take 

 place in the muscular tissue during contraction. The consideration 

 of this branch of the inquiry will form the subject of the second part 

 of the Memoir. 



*' On the Existence of Multiple Proportion in the quantities .of 

 Heat produced by the Chemical Combination of Oxygen and other 

 bodies." By Thomas Woods, M.D. 



This paper is, in substance, the same as a former paper, bearing a 

 similar title, read before the Royal Society on the 10th January 1856, 

 but contains a more detailed account of the mode of performing the 

 experiments. A repetition of the experiments mentioned in the 

 former paper has led to very nearly the same numerical results, 

 except in the case of molybdenum, which is found to give 4*8 ther- 

 mal units by combining with oxygen, instead of 3 "38, the number 

 formerly given. 



" Researches into the nature of the Involuntary Muscular Fibre." 

 By George Viner Ellis, Esq., Professor of Anatomy in University 

 College, London. 



Having been unable to confirm the statements of Professor Kolliker 

 respecting the cell-structure of the involuntary muscular fibre, the 

 author was induced to undertake a series of researches into the nature 

 of that tissue, by which he has been led to entertain views as to its 

 structure in vertebrate animals, but more especially in man, which 



