PHYSICAL ANTECEDENTS OF SCIENCE 117

and wherein the ultimate filaments of the auditory nerve

terminate.

The organ of smell is composed of minute terminal fila-

ments of very delicate nerves (olfactory nerves), which pro-

ceed downwards, from two special prolongations of the brain,

to the moist membrane which lines the uppermost part of the

cavity of the nostrils.

The organ of taste also consists of minute nervous fila-

ments, distributed in the tongue and the hinder portion of

the palate, which filaments are derived from two gustatory

nerves, by which the gustatory filaments are brought into

direct connexion with the brain, as in the three sense organs

before noticed.

The organ of touch is very widely distributed, consisting as

it does of a multitude of nervous filaments that ramify and

end in the skin, which is, however, very differently supplied

by these nerves in different parts, some parts being much

more richly supplied than others. These fibres are connected

with some part of the nervous axis, either the brain or

the spinal cord.

Having gained an elementary acquaintance with the

structure of the human body, and of its component systems

of organs, we have next to consider what those organs and

systems of organs do, what are their functions, and especially

those of the nervous system.

The functions of muscles everyone is in a general way

acquainted with, />., that their special activity is to produce

motion. To do this they contract, becoming shorter and

thicker, and thus bringing nearer together the two parts to

which the two ends of any muscle may be respectively

attached, and it is by these means that all movements

of the body are effected. Most muscular movements are

voluntary, but others are independent of the will. Such

is the case with those of the heart and alimentary canal.

and wherein the ultimate filaments of the auditory nerve

terminate.

The organ of smell is composed of minute terminal fila-

ments of very delicate nerves (olfactory nerves), which pro-

ceed downwards, from two special prolongations of the brain,

to the moist membrane which lines the uppermost part of the

cavity of the nostrils.

The organ of taste also consists of minute nervous fila-

ments, distributed in the tongue and the hinder portion of

the palate, which filaments are derived from two gustatory

nerves, by which the gustatory filaments are brought into

direct connexion with the brain, as in the three sense organs

before noticed.

The organ of touch is very widely distributed, consisting as

it does of a multitude of nervous filaments that ramify and

end in the skin, which is, however, very differently supplied

by these nerves in different parts, some parts being much

more richly supplied than others. These fibres are connected

with some part of the nervous axis, either the brain or

the spinal cord.

Having gained an elementary acquaintance with the

structure of the human body, and of its component systems

of organs, we have next to consider what those organs and

systems of organs do, what are their functions, and especially

those of the nervous system.

The functions of muscles everyone is in a general way

acquainted with, />., that their special activity is to produce

motion. To do this they contract, becoming shorter and

thicker, and thus bringing nearer together the two parts to

which the two ends of any muscle may be respectively

attached, and it is by these means that all movements

of the body are effected. Most muscular movements are

voluntary, but others are independent of the will. Such

is the case with those of the heart and alimentary canal.