494 Prof. W. A. Osborne and Mr. W. Sutherland. [July 5, 



Fig. 9 shows the results of an experiment with the bladder of a large 

 Newfoundland dog 24 hours after death. As with the balloon, I anticipated 

 that here a hyperbolic curve was present, and calculated by the three-point 

 method the value for a to be 0*071, b to be 179. Here it will be seen that 

 from radius l - 93 to radius 2 - 88 a distinct approximation to a rectangular 



350 1 



3 CO 



250 



o 



O 1 2 3 4 5 



Radius in centimetres. 



Fig. 9. 



hyperbola is manifest. But even here, though a can be made zero without 

 appreciably altering the constancy of c, the value for b likewise does not 

 allow us to apply to this bladder the formula for a perfectly elastic 

 substance. 



A number of bladders of various animals were investigated. I give here 

 the results obtained with the bladders of two monkeys and a cat (fig. 10). 



It must be remembered that the elastic tissue of a viscus is not a homo- 

 geneous membrane, but a web of elastic fibres with a variable amount of 

 inextensible white fibres intermixed. This fact must always complicate 

 physical investigations on the elasticity of animal membranes, even if the 

 isolated elastic fibres present obeyed some simple physical law.* When we 



* A research on the elastic constants of the ligamentum nuehce is at present being 

 conducted in my laboratory. 



