Page:Observations on Man 1834.djvu/119

 that the medullary part of the brain, or of the spinal marrow, or the nerve itself, in all which the vessels are extremely fine, and therefore liable to obstructions, especially in old age, become opaque, and unqualified to receive and transmit vibrations freely, according to Sir Isaac Newton’s opinion. Hence a diminution or entire loss of sense or motion, or both, may follow, according to the degree and extent of the obstruction and opacity. The voluntary power of motion is soon lost, as being an acquired faculty, and depending upon associated circumstances, and memory. But if there be any degree of inflammation in the fine vessels of the motory nerves, or of the corresponding parts of the brain, this may occasion convulsive motions; and, for the same reason, an inflammation in the sensory nerves, or their origins in the brain, may occasion pain. Now it is reasonable to expect such inflammations in many cases as a consequence of the obstructions, and both convulsive motions and pains are often found to attend paralytic affections.



the active liquors, infused by venomous animals after they bite or sting, operate, in part, by the violent vibrations which they excite in the living parts immediately affected, and which are thence propagated along the nerves up to the brain, and also along the surface of the body, by means of the continuity and uniformity of the skin, may appear from the following reasons:

First, As the solids and fluids seem, in general, equally concerned in all the natural functions, and morbid deviations from them, it is most reasonable to refer part of the effects of venomous bites and stings to each. But it is difficult to conceive how these poisons should have any immediate effect upon the solid nervous capillaments, but by agitating their parts.

Secondly, The active particles of these poisons, which are able, in so small a quantity, to produce such violent disorders, and sometimes in a very short space of time, may well be conceived able also to agitate the nervous parts with strong vibrations.

Thirdly, If we suppose their first and most immediate effect to be upon the fluids, yet this may, or must, be agitations, that will afterwards be communicated to the solids.

Fourthly, The vibrations of the medullary particles, mentioned in this theory, seem peculiarly suited to answer the several quick and surprising effects of these poisons. The pain, swelling, redness, and lividness, all around the part affected, may easily be derived from the vibrations propagated all around. Oils and fats, rubbed upon the part, may, by damping these, prevent the ill