Mr BAXTER, ON ORGANIC POLARITY. 251 



The amount of deflection of the needle would vary according to the delicacy of the 

 instrument employed ; with an ordinary galvanometer, consisting of but few coils, the deflec- 

 tion was from 3* to 8" or 10°. 



When the electrode, instead of being in contact with the venous blood, is in contact 

 with the arterial blood, or the surface of the mesentery, the efi'ects upon the needle are 

 the same, as far as the direction of the current is concerned, but the amount of deflection 

 may not be so great. 



Let us now endeavour to explain these results according to known actions, such as 

 the chemical reaction of two fluids upon each other, or to the heterogeneity of fluids, as it 

 is sometimes called. If, for example, a glass cell be taken having a porous diaphragm in 

 its middle, such as a piece of membrane, so as to divide it into two cells, and into one 

 compartment we pour an acid solution, and into the other an alkaline solution, and then dip 

 the platinum electrodes of a galvanometer into each of these cells, an effect upon the needle 

 is produced indicating the electrode dipping in the acid solution to be positive to the other. 

 These facts, which have been well worked out by Becuuerel*, may be enunciated in the 

 following proposition : during the reaction of two fluids upon each other, that which per- 

 forms the part of an acid takes positive electricity, and that of an alkali, negative 

 electricity. 



In experiments upon animals, as just related, it was found that the electrode in 

 contact with the venous blood ' was positive to the other, excepting when there was much 

 acid in the stomach, and then the electrode in contact with the mucous surface of the 

 stomach was positive to the other in contact with the blood. Now in order to explain 

 these results, under the supposition that they arise from the chemical reactions of the 

 fluids upon each other, it must be supposed that when the electrode in contact with the 

 venous blood is positive to the other, that then the blood acts as an acid, and not only 

 so, but combines with the substances or fluids in the intestines. When it is found, 

 however, that the electrode in contact with the stomach is positive, then it may be sup- 

 posed, and rightly so, that the results are due to the chemical reactions which occur in 

 that organ between the acids and other fluids that are there found. But should we be justi- 

 fied in supposing that when the electrode in contact with the blood is positive to the other in 

 the stomach, the stomach being empty or containing but little acid, that then the blood is 

 acting as an acid ? Here, as in the intestines, it would be necessary to assume that imme- 

 diately after the separation of the secreted product (the acid) from the blood had taken place, 

 that they then immediately recombined, and not only so, but that the blood, in direct opposi- 

 tion to the well-known fact of its alkaline characters, must be acid in order to account for the 

 effects produced. It would, therefore, appear that no grounds exist for believing that the results 

 obtained in the living animal can be considered as entirely dependent upon the mere reaction 

 of the heterogeneous fluids upon each other, upon their combination for example ; and with 

 out stopping to adduce more arguments against this supposition, let us now proceed to com- 



• Loe. cit. Vol. II. p. 77. 



32—2 



