196 



THE CELL AND PROTOPLASM 



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10' 



Fig. 5. Sliorteniug of an isolated frog muscle fiber in isosmotie calciuin cliloridc solution. The succes- 

 sion of stages is from left to right, as on a printed page. The first photograph was taken in Ringer's 

 fluid; the second, 10 seconds after the addition of calcium chloride. Siil)so(iueiit iiictures were taken at 



10 second intervals. 



