CONCLUSIONS IOI 
blaze up. It no longer reacts to a stimulus. Nearly all 
kinds of tissues show these blaze currents as long as 
they are alive, and the outburst is not only a sign of life, 
but an index of the amount of life. Life and electricity 
are inextricably bound up together. In the sea algae 
alone Waller failed to find this blaze current, but he does 
not doubt that it exists there. One does not obtain 
it for the reason, probably, that the salts of the sea-water 
close the current through the tissue rather than through 
the galvanometer. Perhaps a low-resistance galva- 
nometer would detect it here too. This sign of life of 
Waller is in many ways the most convenient that we 
have, if only we have the apparatus for the detection 
of these currents ready at hand and set up for use. 
But up to this point we were still in the dark regarding 
the cause of this electrical response. We could not know 
whether it was due to a physical or a chemical change 
in the tissues. It might be due to some change of 
permeability of the tissues, or it might be due to a chem- 
ical change. Waller believed it to be caused by the 
latter, and his conclusion was undoubtedly correct. 
Waller also observed that following this electrical 
display there was a sudden lowering in the electrical 
resistance of the pea or other tissue. This might 
also be called a sign of life, but it is not so clear and 
striking as the blaze current. Evidently this is by no 
means so reliable a sign of life as the other. The de- 
creased resistance might be due to a physical change of 
state of the protoplasm or of the membranes, so that the 
salt ‘solution became more continuous; or it might be 
due to the stimulation increasing in some way the ions in 
the protoplasm. It is impossible to say which. 
