ACTION OF HEAT ON THE EXCISED HEART 



115 



mersion a new change occurred, viz. a gradual and regular contraction. 

 This is the production of heat rigor. The heart was kept at this tem- 



perature for four minutes and was then cooled. No relaxation occurred, 

 though after three minutes the heart once more regained a rhythm^ 



though of much weaker force than before. 



i2 



