24 EXPERIMENTS ON THE CIRCULATION 



and to attempt certain modifications of the experi- 

 ment. The facts thus obtained will, I think, enable 

 us to explain, with more precision than has hitherto 

 been attempted, the true reason of the variable 

 nature of the effusion in different instances : and as 

 this involves physiological and pathological points 

 of some importance, the question may not be deemed 

 unworthy of the consideration of the Society. 



As a full description of each experiment must 

 necessarily involve much repetition, and might, 

 therefore, tend to weary and distract the attention, 

 I shall in this place content myself with relating 

 those general results which bear directly on the 

 main object of this communication, leaving the par- 

 ticulars of each experiment to be more minutely 

 described in the appendix to these remarks. With 

 the exception of the first, all these experiments were 

 performed on the kidneys of rabbits. The animals 

 employed varied much in age, size, and condition ; 

 and as the strength of the system exerted a very 

 material influence in modifying the nature of the 

 effusion, each experiment must be considered by 

 itself, in order to arrive at a strictly accurate con- 

 clusion. 



My reasons for selecting the kidney were the 

 following : 



This organ can be readily and quickly exposed in 

 the lower animals, and its artery, vein, and duct, 

 (which constitute almost the sole bonds of union 

 between it and the rest of the body,) may be sepa- 

 rately secured by ligature ; so that we not only have 



