of the animal system to accumulate
electricity, as in these it is used as a weapon of defence, or for the
purpose of taking their prey.

Some have believed that the accumulation or passage of the magnetic fluid
might affect the animal system, and have asserted that the application of a
large magnet to an aching tooth has quickly effected a cure. If this
experiment is again tried in odontalgia, or hemicrania, the painful
membrane of the tooth or head should be included between the south and
north poles of a horse-shoe magnet, or between the contrary poles of two
different magnets, that the magnetism may be accumulated on the torpid
part.

6. _Oxygenatio sanguinis._ The variation of the quantity of oxygen gas
existing in the atmosphere must affect all breathing animals; in its excess
this too must be esteemed a stimulus; but in its natural quantity would
seem to act as an influence, or cause, without which, animal life cannot
exist even a minute. It is hoped that Dr. Beddoes's plan for a pneumatic
infirmary, for the purpose of putting this and various other airs to the
test of experiment, will meet with public encouragement, and render
consumption, asthma, cancer, and many diseases conquerable, which at
present prey with unremitted devastation on all orders and ages of mankind.

7. _Humectatio corporis._ Water, and probably the vapour of water dissolved
or diffused in the atmosphere, unites by mechanical attraction with the
unorganized cuticle, and softens and enlarges it; as may be seen in the
loose and wrinkled skin of the hands of washerwomen; the same probably
occurs to the mucous membrane of the lungs in moist weather; and by
thickening it increases the difficulty of respiration of some people, who
are said to be asthmatical. So far water may be said to act as an influx or
influence, but when it is taken up by the mouths of the absorbent system,
it must excite those mouths into action, and then acts as a stimulus.

There appears from hence to be four methods by which animal bodies are
penetrated by external things. 1. By their stimulus, which induces the
absorbent vessels to imbibe them. 2. By mechanical attraction, as when
water softens the cuticle. 3. By chemical attraction, as when oxygen passes
through the membranes of the air-vessels of the lungs, and combines with
the blood. And lastly, by influx without mechanical attraction, chemical
combination, or animal absorption, as the universal fluids of heat,
grav