12 



Itagaki 



the intestine of the rat. Without exception these showed increase of tone, 

 although occasionally this was preceded by a short period of relaxation. 

 Fig. 11 shows a typical experiment. 



Fig. 11. — Excised portion of small intestine of rabbit (whole tube). Showing increase of tone 

 caused by immersion in 5 per cent, corpus luteum extract. The extract was added at the 

 point marked by the arrow. 



Fig. 12. — Longitudinal strip of small intestine of rabbit. Showing diminution oi 

 tone with cessation of the rhythmic movements as the result of immersion in 

 5 per cent. eoriUTs Inteum extract. 



Fig. 13. — -Portion of colon of rabbit (whole tube). Showing diminution of tone and 

 abolition of rhythmic movements caused by 2 per cent, corpus luteum extract. 



