102 



INFLUENCE OF TEMPERATURE ON BIOLOGICAL SYSTEMS 



depolai-izatiun is coupled to the formation of the activated unit A^NI,,/' 

 (equilibrium A) in this manner. Thus, with a AV of 120 cc/mole for the 

 pK per active site, the AV of 360 cc/mole would govern the formation 

 of each activated unit and a AV of 720 cc/mole would result from two 

 such units being activated per unit of activator Cd . 



Earlier in the present paper, the decrease in tension at the higher 

 temperature was attributed to the duration of the 'active state' being 

 insufficient to permit the full development of tension. The compression 



Fig. 10. M.vograms of the auricular mu.scle of Pseudomys elegans illustrating the 

 effects of abrupt compression to 4,000 psi at various times during the contraction 

 cycle. Temperature 20°C. Myogram C, recorded at atmospheric pressure: P at 4,000 

 psi, the presure being applied 15 seconds before stimulation. In remaining records 

 the time of abrupt compression is indicated by the displacement of the tension record. 



data, however, indicate that the larger tensions depend on equilibrium (A) 

 and hence the development of the 'active state.' The development of this 

 state is generally considered to occujiy only the latent period plus the 

 initial one-tenth of the contraction phase. The question at issue, there- 

 fore, is whether a compression during this brief period is sufficient to 

 produce the large contractions appearing under a sustained pressure. 



In a muscle at 20°C the tension developed under a sustained pres- 

 sure is 2.5 times greater than in a control at atmospheric pressure 

 (fig. 10). However, when the muscle is stimulated and then abruptly 

 compressed to this pressure after only one-fifth of the tension has de- 

 veloped, the resulting contraction is only about 12% greater than the 



