73 6 Irreciprocal Conduction in the [December, 
below it to the lateral surfaces, whilst those issuing from 
the back-surface return to the belly-surface. Within the 
columns there is a current from the belly to the back. If 
we now suppose that in the conductive mass there are, 
besides the first column, other similar columns with parallel 
axes, the lines of the current in any given surface-element of 
the external space are compounded according to the paral- 
lelopipedon ot forces. But, as each column represents for 
all the others a portion of the external space, each is tra- 
versed in a heterodromous direction by a portion of the 
current-lines of all the others. 
For any given part of the external space the other columns 
form, for the lines of current impinging upon them, a by- 
circuit. The worse this conducts the stronger are the 
currents passing through the portion of space in question. 
If we imagine all the other columns insulating, the action 
of the one column upon the part of the external space in 
question will be strengthened. 
[It will be well to bear in mind that the word “ column ” 
as here employed signifies a galvanic combination, and is 
used as being less misleading than “ battery.”] 
The elearic organ is not, indeed, an insulator, but it 
possesses, as the above-mentioned investigations show, the 
power of irreciprocal conduaion. The current-lines are all, 
where they impinge upon the organ, heterodromous. Con- 
sequently they encounter in the organ a resistance which 
has praaically the same effea as if the organ were a non- 
conduaor. In virtue of irreciprocal conduaion there occurs 
the remarkable phenomenon that each column conducts its 
own homodromous current relatively well, but blocks the 
way for the heterodromous current-lines of all other columns. 
As this applies to all the columns, the current-lines of all 
are compelled to take the circuitous route round the edges 
of the elearic organ. The total current in the external 
space consequently increases in density or in physiological 
aaion. 
The concluding observations of Professor Du Bois 
Reymond are here given verbatim : — 
“ I formerly succeeded, when examining the elearical 
fishes, in deteaing surprising instances of that organic 
purposiveness which fills anew even the stria adherent of 
mechanical causality with astonishment. I showed how 
the form of the elearic organs of the torpedo on the one 
hand, and of Gymnotus electncus and il I alapterunis clectvicus 
on the other, is adapted to the different conduaive power 
of sea-water and fresh water ; how, during the growth of the 
