270 Prof. Potter. Electrical Effects accompanying the [July 14, 



At this stage the action of yeast was also studied, and this proving a very 

 convenient substance for experiment, further investigation of bacteria was for 

 the present abandoned. 



The employment of this form of galvanic cell may be usefully extended to 

 the observation of other physiological processes, and it will be of interest to 

 note some electrical effects indicated during the conversion of venous to 

 arterial blood and vice versd. 



A quantity of fresh warm blood was obtained, a part of which was poured 

 into a parchment tube and part placed in the jar surrounding it. With a 

 platinum electrode in the jar and in the parchment tube, it was found that 

 arterial blood was zincative to venous blood. Many trials made, by alternately 

 forcing air or carbonic acid through the blood in the jar or in the tube, 

 showed that the oxygenating stream raised the potential of the blood, so that 

 an electric current passed in the cell from the arterial to the venous blood ; 

 with the entering stream of CO2, however, the potential was lowered and an 

 electric current was produced in the opposite direction. Thus the arterial 

 and venous bloods possess a contrary electrical sign. As a corollary it would 

 seem that this change of sign may play an important part in the electro 

 cardiogram of the heart, and that when arterial is converted into venous 

 blood this change of sign may be looked for as one of the accompanying- 

 events. 



Comparison with a Galvanic Cell. 



The study of the electrical effects during well-known chemical actions by 

 means of a galvanic cell constructed on the principle already described is of 

 much interest for comparison with the electrical effects of fermentation. 



A glass jar containing a porous pot, into each of which a dilute solution of 

 sulphuric acid is poured so that the level of the outer and inner fluids should 

 be the same, a pair of platinum electrodes inserted one in the jar and one in 

 the porous pot, and a little zinc added to either the outer or the inner 

 fluid, constituted a cell comparable with the glucose-yeast cell previously 

 described. 



With such a cell, using a 10-per-cent. solution of sulphuric acid and 

 5 grammes of granulated zinc, the condenser and galvanometer gave an 

 E.M.F. of 07 volt (see fig. 6). The direction of the current in the cell was 

 from the sulphuric acid and zinc to the sulphuric acid, and thus followed the 

 same course as that observed in the case of glucose and yeast. The curve 

 indicating the E.M.F. in volts is also developed in a manner parallel to that 

 of the yeast and glucose. The galvanometer showed no immediate effect 

 following the introduction of the zinc, but during an interval of 8 minutes 



