THEIR CHEMICAL RELATIONS. 69 



fibre. He found that both kinds of muscle were perfectly identical 

 in composition (52'3 of carbon, 7*2-- of hydrogen, and 15'3 of 

 nitrogen). We think that this coincidence scarcely proves anything 

 more than the insufficiency of our elementary analyses ; for sup- 

 posing that the fibre-cells of smooth muscle were identical with the 

 fibrils of striped muscle, it appears singular that the presence of 

 sarcolemma and of tracheal ramifications in the one tissue, and of 

 fibres of connective tissue in the other, (that is to say, of foreign 

 substances, which cannot be removed by the most careful prepara- 

 tion,) should not induce any difference in the results of the analyses. 

 We do not, therefore, think that we are justified in drawing a con- 

 clusion in favour of the identity of composition of the organic 

 elements of motion from these analyses, although they were un- 

 doubtedly conducted in accordance with the best chemical methods. 



If, as it would appear, smaller quantities of carbon and nitrogen 

 have been found to be present in the tissues which have been 

 analysed than in fibrin and albumen, it is more probable that 

 the difference is rather owing to the amount of connective tissue 

 and of chitin, than to a different composition of the contractile 

 elements themselves. 



We have, therefore, regarded it as more in accordance with the 

 inductive method to institute, for the purpose of comparison, various 

 elementary analyses of this substance, which is extractible from 

 every contractile tissue by dilute hydrochloric acid, first precipi- 

 tating it by a dilute solution of soda, and then extracting it with alco- 

 hol and ether. Although we have not so far deceived ourselves as 

 to regard as perfectly pure this matter which, at all events, is mainly 

 derived from the substance of the contractile fibre-cells, (such a 

 supposition being controverted on chemical as well as histological 

 grounds,) we yet believe that the analyses of this matter, obtained 

 from different compound contractile tissues, are better adapted 

 for comparison, and lead to more reliable results, than the 

 analyses of the complex tissues themselves. And in point of fact, 

 this cell-substance, which is soluble in water containing hydro- 

 chloric acid, invariably presented the same composition, whether it 

 had been obtained from the muscular coat of the stomach of the 

 pig, or the middle arterial coat of the ox, or the tunica dartos, or 

 the bladder. It also appeared that this substance, which is 

 derived from smooth muscular fibres, has the same composition as 

 the analogous substance derived from striped muscular fibres, 

 which was first obtained by Liebig and analysed by Strecker. As 

 we shall have to consider more fully in another portion of this 



