STRUCTURE OF UNSTEIPED MUSCLE. 583 



interspaces between the bases of the papillae. Hence, 

 when it contracts under the influence of cold, fear, elec- 

 tricity, or any other stimulus, the papillae are made 



Fig. 148.* Fig. 149^ 



unusually prominent, and give rise to the peculiar rough- 

 ness of the skin termed cutis anserina, or gooseskin. It 

 occurs also in the superficial portion of the cutis, in all 

 parts where hairs occur, in the form of flattened roundish 

 bundles, which lie alongside the hair-follicles and sebaceous 

 glands. They pass obliquely from without inwards, em- 

 brace the sebaceous glands, and are attached to the hair 

 follicles near their base (fig. 150). Fibres of this tissue, 

 also, constitute part of the walls of most gland-ducts, 

 and are concerned in the propulsion of the contents of these 

 canals. 



* Fig. 148. Muscular fibre-cells from human arteries, magnified 

 350 diameters (Kolliker). a, natural state ; b, treated with acetic acid. 



f Fig. 149. Plain muscular fibres from the human bladder, mag- 

 nified 250 diameters, a, in their natural state ; b, treated with acetic 

 acid to show the nuclei. 



