212 Caroline MoGill, 



Roulé's idea was that the sarcoplasm is entirely distinct from the 

 protoplasm, being merely a product of the granular protoplasm of the 

 original mesenchymal cell. 



Minot (1892) stated that smooth muscle develops from the mesen- 

 chyme, but that concerning the details of transformation we have 

 little information. 



Heidenhain, M. (1893) described the smooth muscle in the skin 

 glands as arising from the ectoderm of the gland wall itself, and 

 claimed that, even in the adult, intercellular bridges occur between 

 the epithelium and the muscle. 



Marchesini and Ferrari (1895) did not trace the minute cyto- 

 genesis, but they claimed that each smooth muscle fiber is derived 

 from several embryonic cells. These cells, at the time the flbrillae 

 are forming, are uniting together in twos and threes. The nucleus of 

 the most central cell of the mass persists, the others disappear. They 

 also found that in early development smooth and striped muscle show 

 exactly the same structure, striped being further differentiated than 

 smooth muscle. 



Nussbaum, M. (1900) in man, found that the sphincter muscle of 

 the pupil arises from the ectoderm of the optic vesicle. 



Working upon the development of the intrinsic muscles of the 

 eye, Szili (1901) claimed that both the sphincter and dilator of the 

 pupil develop from the wall of the optic vesicle. The connective 

 tissue surrounding the muscle fibers arises from the neighboring mesen- 

 chyme, and grows in after the muscle is well formed. Szili ended 

 his paper by saying that probably other, and possibly all, smooth 

 muscle arises from epithelium. 



In fishes, Nussbaum (1902) discovered that the retractor of the 

 lens is of ectodermal origin. 



Herzog (1902) worked upon the comparative development of the 

 intrinsic eye muscles, having investigated a large number of verte- 

 brates. In every case, he found that the sphincter and dilator of the 

 pupil arise from the ectoderm and the ciliarj^ muscle from the mesoderm. 



In the embryo of the mouse, Kotzenberg (1902), has studied the 

 development of the muscle surrounding the primitive bronchi and, in 



