698 



THE MICROSCOPE. 



possess important nervous functions ; and are now known 

 as " ganglionic cells." 



The muscular fibre, known as tlie 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 : be was 

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

 the striped muscular fibre is originally composed of 

 similar elements to the unsiriped, 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 sjilit into smaller 

 fibres {fibrillar). 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 surroundincr 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 

 Fiv^. ?i29.— A portion of the. iuvnivn- to be oue or two in conuexion 



tuni viviicular Jlhre surrounding •,•• i t_ • p n- i 



the hair. witli cacli nau'-ioUicle, arising 



from the more superficial parts 

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

 close l)ehind 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 tlirust up the hair-follicles and depress the inter- 

 mediate portions of skin, and thus produce that peculiar 



