Popular Lectures on Zoonomia

I

Inflammation, illustrated

sthenic

asthenic

of gout asthenic

Iron, contained in the blood

L

Lacteals, described Life, principle of Light, its properties its exciting power Lungs, circulation through Lymphatics described

M

Muscles, mechanical action of Music, its effects

N

Nerves, their distribution

Nervous and bilious, terms sometimes used without ideas

diseases (so called)

diseases really so

Newton, his query about elastic fluid misapplied

even his conjectures important

discovers the laws of sound

his reason why the crystalline is densest in the middle

knew not the cause of gravitation

Nonnaturals, misapplication of that term

Nosology

O

Odours, extreme subtilty of Haller, &c. fail in classing them convey nourishment Opium, its intoxicating effects its use in gout Organs, digestive Oxygen, experiments with connected with excitability

P

Pain encreases mental energy Passions of the mind, their effects Pendulums, laws of Peristaltic motion Physiology, its importance Pulse, the phenomena of

R

Respiration, organs of

how performed

analogous to combustion

chemically explained

S

Schools, their temperature ill regulated

Sensation

organs of

more acute by pain

Senses, general account of

external and internal

Skin

Sleep, accumulates excitability

Smell

different in different animals

Blumenbach's opinion on

diseases of

Sound, production of

media of

illustrated

velocity of

musical

reflection of

Spallanzani, his experiments on digestion

Spirituous liquors, their effects

a singular mode of correcting the abuse of

Squinting, &c.

method of cure

Stomach

diseases of

Study, debilitating effects of

T

Taste diseases of Temperancc Temperature of animals, specific and uniform Touch the basis of the other senses Typhus, Dr. Garnett's treatment of Dr. Currie's ditto

V

Veins, their structure and office

Vision, manner of

opinions on

seat of

why objects appear erect

why seen single

diseases and cure of

Voltaire, his story of Ogul, the epicure

W

Water, the best diluent Wine, its use and abuse

1

[FIGURE] Suppose AC to be a lever, held in equilibrio by the force B and weight W, then the whole momentum exerted at B must be equal to that at W, but the forces will be different. For B x AC = W x AB, and if AC = 10AB, then a force equal to ten times the weight to be raised must be exerted by the muscle. Hence we see, that in the actions of muscles there is a loss of power, from their insertions being nearer the fulcrum than the weight. For example, suppose the deltoid muscle to act and raise a weight of 55 lb.: the weight of the arm is 5 lb., and the distance of its insertion is only 1/3 of the arms length, hence the force exerted must be (55 + 5) x 3 = 180 lb.

[FIGURE] But by this contrivance we gain a greater extent of motion, and also a greater velocity, and both with less contraction. Let A be the centre of motion, or articulation; B the insertion of a muscle, and AC the length of the lever or bone; then, by a contraction only equal to B_b_, C is carried through C_c_, which is to B_b_ as AC to AB. It is obvious also, that the velocity is greater, since C moves to c in the same time as B to b.

A loss of power is likewise occasioned by the obliquity of the muscular action, and the oblique direction of the fibres.

For, in this case, there is a compound of two forces, and a consequent loss of power: for the forces are proportioned to the two sides of a parallelogram, but the effects produced are proportioned only to the diagonal.