298 Changes in the Muscle Cell of Necturus 



was accepted by a great number of workers, among whom were : Eeniak, 

 43, Harting, 54, Haeckel, 57, Mnnk, 59, Margo, 59, and Krause, 68. 

 A decided advance was made when Thin, 76, found that after gold 

 chloride staining the cementing substance of the earlier writers was 

 revealed as a network whicli Thin considered the contractile part of the 

 muscle-cell. This theory was elaborated by Retzius, 81, Bremer, 83, 

 Carnoy, 84, Melland, 85, Marshall, 87 and 90, van Gehuchten, 88, and 

 Ramon y Cajal, 88, all of whom maintained that the muscle cell contains 

 a contractile reticulum, the meshes of which were filled with a more 

 fluid substance. By some the longitudinal threads of this network were 

 interpreted as fibrillge. Others held that the fluid substance in the 

 meshes of the reticulum coagulated through the action of various agents 

 and thus formed the fibrillse. 



The fibrillar theory was established through the early investigations 

 of Prevost and Dumas, Treviranus and Berres, who regarded the fibrillse 

 as homogeneous structures. The theory was supported by Schwann, 39, 

 Henle, 41, Gerlach, 48, Kolliker, 50 to 00, and others. During recent 

 years it has received further support through the investigations of 

 Rollet, 85 to 91, Eimer, 92, Schafer, 91, Rutherford, 97, McDougall, 97, 

 Heidenhain, 99, and Godlewski, 02, all of wliom regard the fibrillfe as 

 the contractile elements and as arising independently of the cyto-reticu- 

 lum. As to the exact nature of the fibril, however, there are difl'erent 

 opinions. Rollet, Heidenhain and Godlewski consider the fibril as a 

 semifluid homogeneous structure, while Schafer, McDougall and others 

 regard it as regularly segmented and hollow in certain portions. 



A potent argument against the coagulation hypothesis is the fact that 

 the fibrillae have been repeatedly observed in the living fibre. Sachs, 72, 

 and Wagener, 73, observed them in the wing-muscles of insects; Kiefer- 

 stein, 59, and Kolliker, 66, in petromyzon ; Hensen, 68, and many others 

 in the frog; Frederique, 75, in mammals. 



I have repeatedly observed the fibrillse in the living muscle cells of 

 the larval Necturus. A study of the fresh material in norma] solutions 

 shows that the fibrillated portion of the cell is of the same extent as in 

 the fixed and stained material. I^ot only is this true of the diiferent 

 stages of growth, but furthermore, in the same embryo, one can readily 

 follow the decreasing diameters of the fibrillated tracts from the mid- 

 dorsal to the caudal myotomes. A point of capital importance is found 

 in the fact that in Necturus, Amia, Lepidosteus, as my own observations 

 show, and in other forms, as Kaestner, 92, has found, the beginning of 

 fibrillation is coincident with the first contractions. The movements of 



