379 



Nachdruck verboten. 



Nuclear Changes in the striated Muscle Cell of Necturus.^) 



By Albert C Eycleshymek, Instructor in Anatomy University, of Chicago. 



With 3 Figures. 



The following remarks are given as a preliminary to a more 

 extended paper on the structural changes in the striated muscle 

 cell during its growth. The work was done under the direction of 

 Professor Charles S. Minot and while the writer held an Austin 

 Teaching Fellowship in the Harvard Medical School. 



During the past decade the cytological investigations, especially 

 on secretion and regeneration, have led us to regard the nucleus as 

 the primary factor in both chemical and morphological synthesis. 



On the nuclear changes during certain phases of cell life we 

 possess an extensive literature. Concerning the role of the nucleus in 

 histogenesis, however, we know but little. 



For the study of nuclear changes during histogenesis there is 

 probably no cell more suitable than the striated muscle cell, since it 

 is here possible not only to determine with much precision the vol- 

 umetric relations of nucleus and cytoplasm, but also the period of 

 maximal cytoplasmic activity as revealed through the formation of 

 fibrillae. 



The observations of Rabl, Minot and Macallum have shown 

 that peculiar structural changes occur in the nuclei of the striated 

 muscle cell of the Shark, Chick and Man. 



Rabl describes the muscle cells of Pristiurus at the time the 

 first fibrillae are formed and speaks of their nuclei as follows : "Diese 

 Kerne zeigen ein eigentümliches Verhalten, das schon in sehr frühen 

 Stadien angedeutet war. Sie färben sich viel weniger intensiv als die 

 Kerne der übrigen Mesodermzellen und haben ungefähr in ihrer Mitte 

 ein stark lichtbrechendes Chromatinkorn. Es ist dies kein eigent- 

 liches Kernkörperchen, szndern der Querschnitt einer langgestreckten, 

 von vorn nach hinten laufenden Chromatinmasse." 



Minot refers to Rabl's observations and adds: "in the chick 



1) Read before the American Association of Anatomists, Chicago, 

 Dec. 29, 1901. 



