TISSUE CULTURE 



69 



the entire heart. The rhythmic contraction of muscle fibers 

 {e.g., skeletal muscle) may also be observed in culture. 



Fig. 54. — Removing a chick embryo from its shell. 



Fig. 55. — Mounting a bit of chick tissue on a cover slip (the culture charnbers 

 in this case are made by forming a ring of thick petroleum jelly on an ordinary 

 slide) . 



Fig. 56. — Cells (fibroblasts) migrating from the parent tissue (explant) of chick 

 heart. (From a fixed and stained preparation.) 



The most fundamental of the various problems of the tech- 

 nique of growing tissue cells in culture is that of nutrition. But 



