80 



Dr, A. D. Waller. An Attempt to Estimate 



The presence of an unequivocal or homodrome blaze current is in 

 my experience proof positive that the object under examination is- 

 alive. Absence of the effect is strong presumptive evidence that the 

 object is " dead," or rather not-living. It may be in that paradoxical 

 state of immobility which we characterise as latent life, and which we 

 may not characterise as the living state, inasmuch as no sign of life 

 is manifested, nor as dead, inasmuch as the living state can be resumed. 

 An object in this dormant state exhibits no " blaze current " or other 

 sign of life. And although it has capacity of life, and cannot therefore 

 be classed in the category of " dead " things, it is not actually living, 

 and must therefore logically be classed in the more extensive category 

 of not-living things. 



Limiting ourselves to the unequivocal blaze current as the criterion 

 between the living and not-living states, we may formulate the follow- 

 ing practical rule for a summary interrogation of any given object : — 



If the after-currents aroused by single induced currents of both directions 

 are in the same direction, the object investigated is alive. 



Practically, by reason of the fact that most objects of experiment 

 are not physiologically homogeneous, this rule finds frequent applica- 

 tion, inasmuch, as there is a favourable and an unfavourable direction 

 of response, which occurs in the former direction, whether the excitation 

 happen to be in the former or in the latter (e.g., electrical organs, eye- 

 ball, skin, injured tissues animal and vegetable). 



In the case of objects that are physiologically homogeneous or nearly 

 so, the after-currents to both directions of exciting current may be 

 homodrome, i.e., of the nature of unequivocal blaze currents. In such 

 case it generally happens that the two opposite reactions are more or 

 less unequal, by reason of imperfect physiological homogeneity of the 

 mass of matter under investigation. It rarely happens that the 

 physiological homogeneity is such that the two unequivocal blaze 

 currents are quite equal and opposite. 



So that the diagnosis of any suitable object as to its state of life or 

 not-life rests upon the three following types of response : — 



1. Both after-currents aroused by single induction shocks (or by 

 condenser discharges) of both directions are homodrome to the exciting 

 currents. From which it is to be inferred that the object is living. 



2. Both after-currents are in the same direction. The object is liviDg. 



3. Both after-currents are in the polarisation direction. The object 

 is not-living. 



Direction of exciting current - + 



Direction of after-current (1) 



