Picture - Cosmic Polymath

l62 DESIGN IN NATURE
The collared monad is a minute transparent microscopical creature which lives in fluids and consists of a steni
or pedicle by which it is fixed to some foreign object, a pear-shaped body in which can be seen a nucleus several
contractile vesicles, food globules. &c. Projecting from the upper part of the body is a long, slender, tapermg,
hair-like process k^own as the flagellum. Eising from the upper part of the body rs the beautifully moulded,
'^t:l2::X^SrL .o..... monad are rts small si.e, transparency, and simple orga^sation
ft possesses no alimentary canal, no breathing appara,^, ^ cW^> ^;;o^l^^o nm^es, no ner^, r^
Fig. 35. — Collared monad {Monoslga gracilis) fed on
eannine ; very greatly magnified. Shows a pear-shaped body
surmounted by an egg-cup collar. The body terminates in a
stem or pedicle which is broken off. d, Collar ; /, flagellum ;
'/(, nucleus ; cv, contractile vesicles ; fg, fy, food globules.
The arrows indicate tlie dii-ection which the food particles,
floating in the watei', are obliged to take because of the
voluntary well-directed movements of the flagellum (AV.
Saville Kent).
reproduces itself perfectly, and in great numbers. It exhibits
the potentialities and powers of life in their most rudimentary
forms. By feeding the animal on carmine -stained food particles
its several parts and its mode of feeding are brought out in
strong rehef. The most extraordinary part of the collared
monad is its flagellum, a vibratile hair-hke process which is
made to sweep round within the egg-cup collar by a great
variety of voluntary well-directed movements in such a manner
as to produce a succession of currents which cause the food
particles floating in the water in which it is immersed to rise
up in the vicinity of the monad and flow into the open coflar
and downwards in the direction of the body where they are
ongulphed. The flagellum is endowed with, practically, a uni-
versalitv of motioa, and is thoroughly under control. It is a
means to a very obvious end, namely, the securing of food. In
it we behold a voluntary instrument of the first importance to
the well-being, and even the life, of its possessor. It may be
compared to the tongue of the higher animals, composed of a
complicated system of muscles ; the fibres of which run in
longitudinal, transverse, and obhque directions, symmetrically.
The tongue, as is well known, can be made to move in almost
every direction. The other important parts of the collared
monad are its nucleus and contracting vesicles. The nucleus is
a central fundamental structure which plays an important part
in reproduction ; usually dividing into two in that process
to form two new individuals. The contractile vesicles are re-
markable structures from the fact that they are endowed with
spontaneous, independent, rhythmic movements which enable
them to open and close alternately by centrifugal and centripetal
movements with time -regulated beat, after the manner of the
several compartments of the heart in the higher animals. The
contractile vesicles are undoubtedly the harbingers of the heart
whenever and wherever they occur. That a creature so rudimentary
and simple as the collared monad should possess
structures which perform such an important rule in the circulation of the higher animals, up to man, may well
excite wonder, and that wonder is greatly increased when it is stated that they contain neither muscle nor nerve ;
the substances to which we usually refer regulated movements in animals. This marvellous arrangement of life is
strangely enough not confined to the monad and other rudimentary animal forms. It first makes its appearance
in the plant Volvox glohator, whose water vacuoles open and close rhythmically with the utmost regularity and
precision, the vacuoles opening slowly and closing somewhat suddenly as in the ventricles of our own hearts.
The contractile vesicles of plants and the lowest animals teach a very important lesson, namely, that structure
and differentiation, in the ordinary sense, are not necessary to the production of the spontaneous, co-ordinated
rhythmic movements on the integrity of which, in ourselves, life depends. They are utterly inexplicable unless
we refer them to a First Cause and design.
The function performed by the contractile vesicles in the collared monad is not quite understood. They
are supposed to regulate the amount of fluid in the body for the time being, and to assist in the elimination of
effete products. They thus seem to be connected with ingestion and egestion,