PLATE 1 



EXPLANATION OF FIGURES 



1 Normally contracted small intestine of a newborn guinea-pig. X 80. 



2 Small intestine of newborn guinea-pig distended with 150 cm. water pres- 

 sure. X 80. 



3 Normally contracted small intestine of adult guinea-pig. X 80. 



4 Small intestine of same guinea-pig subsequently contracted after disten- 

 t;on similar to that in figure 7. X 80. 



PLATE 2 



EXPLANATION OF FIGURES 



5 Strongly contracted small intestine of adult guinea-pig. X 80. 



6 Small intestine of adult guinea-pig normally distended with food mate- 

 rial. X 80. 



7 Small intestine of adult guinea-pig distended with 150 cm. of water pres- 

 sure. X 80. 



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