90 GENERAL ANATOMY OF THE TISSUES. 



thought to be such, are allied genetically to the transversely 

 striated muscles of the higher animals. 



Their occurrence in the Vertebrata is in some respects 

 peculiar, and I will here mention the following localities in 

 which they are found : In the skin of Birds, as the muscles of 

 the quill-feathers — in this case with tendons of elastic tissue ; 

 in that of the Orang-outan, in the hair-sacs, as in man ; in the 

 iris of the Amphibia ; in the campanula Halleri of the osseous 

 Fishes (Leydig) ; in the swimming bladder of Fishes ; in the 

 lungs of the Frog (in Triton they are here wanting) ; in the 

 mesentery of the Plagiostomata, of Psammosaurus and Le- 

 posternon (Leydig u. Briicke) ; in the genito-rectal muscle of 

 Mammals. In the gizzard of birds these muscles are of a bright 

 red colour, and are united with a tendinous membrane.] 



Literature. — Kolliker, ' Ueber den Bau und die Verbreitung 

 der glatten Muskeln./ in the ' Mittheilungen der Naturf. 

 Gesellschaft in Zurich/ 1847, p. 18, and ' Zeitschrift fur wiss. 

 Zool.,' Bd. I, 1849 ; C. R. Walther, f Nonnulla de musculis 

 lsevibus./ Diss. Lips. 1851. 1 [Jos. Lister, ' Observations on the 

 Contractile Tissue of the Iris/ Quart. Journ. Mic. Sc, vol. I, 

 p. 8, PI. i. — Eds.] 



§ 27. 



Transversely Striated Muscular Tissue. — The elements of 

 this tissue consist essentially of the so-called muscular fibres 

 or primitive muscular bundles, each of which, 004 — 003"' 

 thick, consists of fine fibrils surrounded by a special homoge- 

 neous, delicate, elastic investment, the sarcolemma : the fibrils 



1 [Reichert (Bericht, 1849, Miiller, 'Archiv.,') states that, according to Paulsen, 

 the action of a solution of caustic potass of 50 per cent, causes the smooth muscles 

 to become wavy, and thus to assume a transversely striated appearance under the 

 microscope. Macerated in such a solution for three days, they break up into small 

 globules : striated muscle behaves in a similar manner, and the globules correspond 

 in size to the interval between two striae. 



Eylandt (Obs. Microscop. de musculis organicis in hominis cute obviis. Diss. 

 inaug., Dorp. 1850, c. Tab. lithog.), denies the existence of free smooth muscles in 

 the papilla and areola mammce, in the scrotum, in the skin of the penis or of the 

 prepuce, and in the perinaeum. Nor does he find them in the outer layers of the 

 hair-sacs (apart from the arrectores pil'i), in the glandules sudoriferte of the axilla, of 

 the anus, &c, nor in the glandules ceruminosce. The smooth muscles observed in 

 the papilla and areola mammce, in the skin of the peuis and of the perinamm, he con- 

 siders to belong to a greatly developed vascular layer. (See, however, the remarks of 

 Prof. Kolliker upon Eylaudt's statements, at the end of § 31.) — Eds.] 



