698 



THE MICROSCOPE. 



possess important nervous functions ; and are now known 

 as " ganglionic cells." 



The muscular fibre, known as the non-striated, or invo- 

 luntary, consists of a series of tubes presenting a flattened 

 appearance, without the transverse striae so characteristic 

 of the former : elongated nuclei immediately appear upon 

 the application of a little dilute acetic acid. Professor 

 Wharton Jones first demonstrated this structure in his 

 lectures at Charing Cross Hospital, about 1843 : he was 

 led to infer, from appearances in very young fibre, that 

 the striped muscular fibre is originally composed of 

 similar elements to the unstriped, or plain muscular tissue, 

 which, in the process of deve- 

 lopment, becomes enclosed in a 

 sarcolemma (simple membrane) 

 common to many of them ; the 

 fibres then split into smaller 

 fibres (fibrillce). Thus account- 

 ing for the nuclei of striped 

 muscular fibre; which, accord- 

 ing to his views, are " the per- 

 sistent nuclei of the primitive 

 muscular-fibre cells." 



The non-striated fibre is beau- 

 tifully seen in connexion with 

 the skin surrounding the hairs 

 of the head, a few fibres of 

 which are separately shown in 

 fig. 329. Professor Kolliker ori- 

 ginally described these muscles 

 of the skin, of which there appear 

 Fiij. 329. A portion of (he invoiun- to be one or two in connexion 



tary muscular fibre surrounding ,-, i_ i. j? iv i 



the Mir with each hair-follicle, arising 



from the more superficial parts 



of the outer skin, then passing down to the root of the hair, 

 close behind the fat-gland, and there embracing it. It is 

 indeed most remarkable that skin, when covered with 

 hair, should alone be provided with these muscular 

 fibres ; the effect of the contraction of which must be 

 to thrust up the hair-follicles and depress the inter- 

 mediate portions of skin, and thus produce that peculiar 



