1866.] 



Indications of Animal Electricity. 



163 



decided electroscopic indications of negative electricity indifferently in 

 arterial, venous, or mixed blood ; not unfrequently I have failed to find any 

 such signs. Now and then I have found comparatively feeble signs of 

 positive electricity. In every case also where I have examined blood after 

 an interval of an hour or so from the time when it had flowed fresh from 

 the vessel, I failed to detect any sign of electricity, negative or positive. 

 These experiments no doubt leave much to be discovered in the same 

 direction, but this at least they do, — they furnish the first electroscopic 

 proof of the presence of electricity in living blood. Nay, it is perhaps not 

 too much to say that they supply the first unequivocal proof of electricity 

 in blood, for the current electricity recently obtained from blood by M. 

 Scoutteten and Dr. Shettle may in reality be nothing more than the result 

 of chemical and other changes produced by the blood upon the terminal 

 wire of the galvanometer used in these experiments. 



Third Series. — Experiments which furnish electroscopic indications of 

 electricity in living nerve-tissue. 



The plan adopted in this series of experiments was to tie a loop of silk 

 braid to the part to be experimented on, and to use this loop as the means 

 for bringing this part to the cap of each electroscope in turn. 



Exp. 1 1 . — The medulla oblongata of an ox obtained a few minutes after 

 the animal had been killed in the ordinary way in the shambles, was the 

 part used in this experiment. At one time the cut surface exposing the 

 transverse section of the fibres and the internal grey matter was brought to 

 the caps of the electroscopes ; at another time the uncut surface corre- 

 sponding to the longitudinal surface of the fibres was treated in this man- 

 ner ; and in each case the movements of the gold leaves were indicative of 

 the action of positive electricity = 6, or thereabouts, the only difference 

 perceptible being a slight one of degree. The average movements obtained 

 were those of d. d. = 4 in the negative electroscope, and i. d. = 8 in the 

 positive electroscope. 



Exp. 12. — The brachial enlargement of the spinal cord of an ox, 

 taken out of the canal when the carcass was being split into two lateral 

 halves at the usual time, that is, about half an hour from the moment 

 when the animal had been felled with the pole-axe, was used in this 

 experiment, and the result was d. d. = 4 in the negative electroscope, and 

 i. d. = 8 in the positive electroscope. It was found also that this result 

 was the same, except in some trifling difference in degree, in the case where 

 the transverse sectional surface of the fibres was brought to the caps of 

 the electroscopes, and in the case where the longitudinal surface of these 

 fibres, natural or artificial, was examined in this manner. 



Exp. 13. — Here the part examined was the posterior lobe of the cere- 

 brum of a sheep which had been killed in the usual way a few minutes 

 previously in the shambles. No time was lost in making the necessary 

 preparations, but not the slightest indications of electricity were obtainable, 



VOL. XV. P 



