310 Changes in the Muscle Cell of Neetiirus 



Fig. 12. — Transverse section of myoblasts from 26 mm. embryo, showing the 

 complete fibrillation of the myoblast and the eccentric position of the nuclei. 

 X 500. 



Fig. 13. — Transverse section of muscle fibre from 2S cm. adult, showing the 

 enormous increase in the number of fibrillse and the redistribution of the 

 nuclei, x 500. 



EXPLANATION OF PLATES II, III, IV. 



In making the drawings of the various nuclei the writer used a Zeiss 

 apochromatic 2.0-mm., homogeneous immersion lens in combination with a No. 

 12 compensating ocular. The drawings were made at the table level under 

 camera lucida projection. The greatest care has been taken to reproduce 

 faithfully the appearances. 



The nuclei were all fixed in Flemming's stronger solution and then stained 

 by Heidenhain's iron alum hematoxylin method or with safranin. It should 

 be added that these stains were supplemented by a number of others, all of 

 which give the same appearances. 



Fig. 14 is a profile drawing of an isolated nucleus, in the resting stage, from 

 a myoblast of the 7 7)im. embryo. 



Figs. 15-26 represent a series of transverse sections of a nucleus in the 

 same stage. 



Fig. 27 represents a drawing of an isolated nucleus, in the resting stage, 

 from a myoblast of a 26 mm. embryo. 



Figs. 28-39 represent a series of transverse sections of a nucleus in the same 

 stage. 



Fig. 41, profile view of an isolated nucleus, in the resting stage, from mus- 

 cle cell of 23 cm., adult. 



Figs. 42-60 represent a series of transverse sections of a nucleus in the 

 same stage. 



