PLAIN OR UNSTEIPED. 



cxxv 



has arrived at the conclusion that it consists of fibres, which are not made up of the 

 cells described, but agree in essential structure with those of voluntary muscle ; and 

 he considers the so-called nuclei as corpuscles belonging to the investing tissue of the 



Fig. LXX. 



Fig. LXIX. 



Fig. LXIX. PLAIN MUSCULAR 

 FIBRES PROM THE HUMAN BLAD- 

 DER, MAGNIFIED 250 DIAMETERS. 



A, in their natural state ; B, 

 treated with acetic acid to show the 

 corpuscles. 



Fig. LXXI. 



Fig. LXXI. MUSCULAR FIBRE- 

 CELLS PROM HUMAN ARTERIES, 

 MAGNIFIED 350 DIAMETERS (K6l- 

 liker). 



a, natural state; b, treated with 

 acetic acid. 



Fig. LXX. MUSCULAR FIBRE-CELL FROM THE MUSCULAR COAT OF THE SMALL INTESTINE, 



MAGNIFIED (Kolliker). 



muscular fibres. "Without denying that there may be a modification or variety of the 

 non-striated muscular fibres not divisible into singly nucleated cells, I nevertheless 

 think that the existence of such contractile cells must now be admitted as fully es- 

 tablished, and that the fibres and bundles of the plain muscular tissue are commonly 

 made up of these cells. 



The plain muscular tissue is for the most part disposed between the coats 

 of the membranous viscera, as the stomach, intestines, and bladder, in the 

 parietes of the air-tubes, excretory ducts of glands, and the like. It is 

 generally collected into larger and smaller fasciculi, which in many cases 

 cross one another and interlace. The fasciculi are connected at their ends 

 with tendinous tissue, and are thus inserted into the membranous and 



