CHAP. IV. §. III. DURING UEINAET SECRETION. 43 



It may just be remarked, that slight effects may 

 be observed when the electrode is in contact with 

 the arterial blood instead of the venous blood, the 

 other being in contact with the urine. But no 

 effects are obtained when one electrode is inserted 

 into the vein and the other into the artery of the 

 kidney. 



Whilst upon the subject of urinary secretion, I 

 may allude to a circumstance of some interest. At 

 the time the original experiments were performed, 

 it was frequently observed that the blood continued 

 to indicate its positive condition, long after the 

 secreting process could have been going on, which 

 led to the belief that the blood might have the 

 power of retaining its peculiar electrical state. Sub- 

 sequent experiments have tended to confirm this 

 opinion, but it was never supposed that the secretions 

 could have the power of retaining their peculiar 

 electrical condition until lately. Beading over some 

 of the Memoirs published at the time of the cele- 

 brated controversy between Galvani and Volta, I 

 was much gratified by accidentally finding a letter 

 written by Vassali Eandi, at that time one of the 

 celebrated Professors at Turin, to M. Delametheie, 

 then Secretary to the Eoyal Academy of Pai'is, who 

 requested his opinion "upon Galvanism and the origin 

 of Animal Electricity,'' and to which I have referred 

 in chap. i. The position these two individuals 

 held might be adduced as giving some weight to 

 their authority, Amongst other arguments that 



