CHAP IV. DURING SECEETION. 53 



whether the effects can be entirely due to thermo- 

 electric actions. But there can be no doubt that a 

 part of the effects may be referred to these circum- 

 stances, and partly also to catalytic actions, and they 

 must therefore be taken into consideration when 

 judging of the final result upon the needle. 



The results recorded in the present chapter tend 

 to establish the following conclusion, viz. that the 

 act of secretion in the living animal is accompanied with 

 the manifestation of cuebent fokcb ; and the phe- 

 nomena with which this act of secretion appears to 

 be the most intimately related are those that occur 

 in the voltaic circle. A difficulty may arise to some 

 minds in perceiving this relation, from the circum- 

 stance that in the ordinary voltaic circle metals are 

 employed. If we bear in mind that the metals, 

 although one of them is usually acted upon, serve 

 principally as condtictors, and that they are not 

 essential for the developement of the power, this 

 difficulty will be easily removed. Now as the mani- 

 festation of curreM force during, the actions which 

 occur in the voltaic circle are considered as evidence 

 oi polar action, there can be no reason why it should 

 not be so considered in regard to organic action, 

 viz. during secretion; but before we arrive at this 

 conclusion, let us compare the phenomena of secretion 

 with another class of facts, viz. with those of osmose. 



Professor Graham has communicated a very valu- 

 able Paper to the Eoyal Society, entitled. On Osmotic 



