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Whence proceeds the permanent relief obtained in them? The 
galvanic experiments lead us to expect relief to the dyspnoea 
while the stream of gaivanism passes through the lungs; but on 
what principle shall we explain the permanency of the relief af- 
forded? ‘The following observations appear to throw some light 
on this subject. There are two ways in which av organ may be 
deprived of its nervous influence, either by a failure of due action 
in the brain and spinal marrow, the sources of nervous influence, 
or a failure of due action in the nerves of the organ affected by 
which this influence is conveyed.: It is no longer conveyed by a 
nerve which has been divided, or around which a ligature has 
been thrown. Now we have reason to believe that habitual 
asthma arises not so much from a fault in the brain and spinal 
matrow, as in the nerves of the lungs ; because, did the degree 
of dyspnoea, which we often witness in this disease, arise from 
failure in the general source of nervous influence, this failure 
must be sufficient to appear in the derangement of ail the nervous 
functions ; whereas in habitual asthma, we often find the fune- 
tion of the lungs alone affected; and when general failure of 
nervous influence is observed, it is evidently the effect of im- 
peded respiration, appearing only after the latter has continued 
for some time, and varying as it varies. The effect produced by 
galvanism, when it performs a cure in habitual asthma, therefore, 
does not appear to be its having occasioned a permanent supply 
of nervous influence, but its having cleared, if | may use the ex- 
pression, the passage of this influence to the lungs. It is not 
difficult to conceive that such an obstruction may exist in the 
nerves as cannot be overcome by the usual supply of nervous in- 
fluence, though it may yield to a greatly increased supply of it ; 
and that it may in some cases continually recur in an equal or 
diminished. degree, while in others, being once removed, the ten- 
dency to it may cease *, 
‘* The foregoing observations seem to explain why other means 
which give a temporary vigour to the nervous system, often, for 
the time, relieve habituai asthma; and sometimes, though rarely, 
cure this disease, ‘The relief obtained from such means being in 
general so much less than that obtained from galvanism, I would 
ascribe to the former oceasioning but little additional supply of 
nervous influence, while by the latter we can make the additional 
supply as great as we please.” 
'* «© What is here said is well illustrated by the effects of valvanism in 
apoplexy. Weé know that in this disease the dyspnoea arises from a failure 
in the source of nervous influence, and the relief obtamed from galvanism 
corresponds with the views afforded by the experiments which have been 
laid before the reader. While the galvanism passed through the lungs the 
dyspnoea was as much relieved as in habitual asthma, but when it ceased 
to pass through them, the relief lasted no longer than was necessary for the 
reaccumulation of the phlegm,” 
Early 
