Abdominal Musculature in Cat. 



147 



hour after death the pressure curve more closely approximated 

 the straight line exhibited by any elastic body. 



The condition of pregnancy is of interest in connection with 

 these experiments. Many cats in varying stages of pregnancy 

 were examined. They all, in proportion to their weight, exhibited 

 a greater degree of extension of the abdominal musculature, with a 

 lesser amount of pressure in proportion to volume, than the 

 non-pregnant cats. Even when the abdominal musculature was 

 greatly distended, these cats appeared capable of the accommoda- 

 tion of a relatively large volume of fluid. 



Grey 2 has pointed out that time is an essential factor in the 

 expression of this lengthening of the muscle fiber with no greater 

 degree of tension. It is probable that the conditions of preg- 

 nancy, with the lengthy time factor involved, are far more ideal 

 for demonstrating this particular form of muscular activity than a 

 laboratory experiment can ever be; it is significant that the abla- 



2 Grey, Ernest G., Amer. Jour. Physiol., 45, 272. 



