282 SPECIAL HISTOLOGY. 



properties, which approach those of elastic tissue, I am rather 

 inclined to the opinion, that its function, in the contraction of 

 the fibre, is merely passive. The same may with greater cer- 

 tainty be affirmed of the albuminous fluid uniting the indivi- 

 dual fibrils. Consequently, it is not the muscular fasciculus, 

 in toto } but only the fibrils, which are to be regarded as the 

 contractile elements; a position which is not shaken by the 

 circumstance, that other conditions occur in the smooth mus- 

 cles, and in many muscles in the Invertebrata (those that 

 exhibit no fibrils). 



This is not the place to dilate upon the causes to which the 

 contractions of the muscles are due, and by which they are 

 necessarily produced, and I will merely offer the following 

 remarks. There can be no doubt that the contractility of 

 the muscular substance is a proper and inherent attribute, and 

 only called into manifest action to a certain extent through 

 the nerves ; whilst it is equally certain, that there are no facts 

 which conclusively demonstrate, that the striped muscles contract 

 independently of a previous nervous influence. What the pro- 

 cesses are which take place in the fibrils during the contraction 

 is wholly doubtful ; but it is to be hoped that the further 

 investigation of the laws of the electric currents in the mus- 

 cles, prosecuted in the way so successfully pursued by Du Bois 

 Reymond (' Untersuchungen iiber thier. Electricitat/ Berlin, 

 1848-49), will throw some light upon this, as yet, obscure 

 subject. It would be more than bold to hazard an assertion 

 with respect to the nature and mode of action of the nerves 

 upon the muscles, since we are quite as much in the dark as 

 to the processes which take place in the nerves, as we are with 

 regard to those occurring in the muscles themselves. From 

 the anatomical facts, which prove, that in many animals the 

 motor nerve-fibres come in contact with each primitive 

 muscular fasciculus only at a few points, and never pene- 

 trate into its interior, it is, however, rendered evident, that 

 in the contraction of a muscle, the nervous influence must act 

 from a certain distance. 



The muscles also possess sensibility, though of a rather 

 peculiar kind, because punctures, burns, and incisions into 

 their substance, excite scarcely any sensations worth naming, 

 whilst every muscle, after long-continued activity, as well as 



