CROSS STRIATED MUSCLE IN TISSUE CULTURES 193 



The formation of the muscle buds seems to be inherent in the 

 muscle fiber itself and becomes manifested when the fiber is cut 

 across or is injured. The peculiar form which they take as long 

 narrow fibers is to be attributed to the specific complex of mate- 

 rials which compose the muscle substance and to the dynamic 

 processes which occur there. 



Although the initial stages are much the same in cultures and 

 in regeneration, it is not to be expected even after prolonged 

 cultivation in vitro there will be a redifferentiation of the muscle 

 buds. Especially will this be true, if, as Morgan suggests, the 

 same factors which affect the normal growth and differentiation 

 of the embryo affect in the same way the regeneration of a part. 

 In the healing of wounds a similar process of dedifferentiation 

 followed b}'' a redifferentiation is involved. 



The anastomoses between muscle buds suggests that in the 

 normal muscle there may yet be found a syncytial hke condition 

 even in the adult. It lends some support to Huber's suggestion 

 that muscle may be syncytial in character which suggestion he 

 makes in spite of the fact that he has succeeded in isolating 

 fibers of various lengths. On the other hand, it may be that the 

 pecuhar conditions found in tissue cultures produce conditions 

 not normally present. We have in the past often observed 

 anastomoses of nerve axones in cultures of sympathetic fibers. 

 Even if such phenomena are the result of peculiarities of cul- 

 tures that are not present in the hving organism, they serve to 

 show us at least some of the potentialities of muscle and nerve 

 protoplasm. 



