116 THE SIGNS OF LIFE [LECT. 



able defect in these trials, that they have not and cannot be 

 repeated on the same skin after death ; so that we cannot feel 

 certain that the so-called unequivocal responses have not been 

 due to anomalous polarisation, which with the form of elec- 

 trodes employed was found liable to occur. Amalgamated zinc 

 plates covered with chamois leather soaked in zinc sulphate 

 are rarely free of polarisation currents, ordinary kathodic 

 antidrome as well as anomalous anodic homodrome, and with 

 tetanisation they give a formula in all points similar to that 

 given above. I do not therefore regard the results as being 

 conclusive until repeated with more perfect electrodes. 



The fallacy caused by anomalous 

 B C A polarisation of imperfect electrodes so 

 "<- far from being avoided by the use of 



^ """} tetanising currents is favoured, for we 

 j- > then have to do with antidrome katho- 



( ^ die polarisation by one current plus 



/ homodrome anodic polarisation by the 



opposite current. 



71. A fruitful experiment. Allusion has been made above 

 to the "blaze-currents" of excised human skin ( 53, p. 86), and 

 I should like to bring the point once more under your notice, as 

 it has been for the last few weeks under my close observation. 

 I wanted to know how long after death this sign of life can be 

 detected in the skin itself, and whether the duration of survival 

 is found to vary after various modes of death. The skin is a 

 tissue of quite remarkable vitality ; it seems as if it had learned 

 to resist injury from its surroundings, and to have become tough 

 and hardy of habit. You may have noticed in your rambles logs 

 by the wayside from which young shoots have sprung from 

 surviving subcortical tissues ; perhaps you have heard that on 

 Napoleon I.'s removal from St Helena to the Invalides, his toe- 

 nails were found to have grown through his boots a sign of the 

 extraordinary vitality of the cells of the nail-matrix, or of the 

 perishable quality of boot-leather nearly twenty years had 

 elapsed between burial and exhumation. There is no doubt 

 whatever that the hair grows after death. 



