RHYTHMIC MOVEMENTS IN PLANTS AND ANIMALS 251 



Under 6 (Emotions) fall the rhythms which result in sighing, sobbing, crying, laughing, impulses of love, 

 hatred, &c. 



Under 7 (Reproduction) fall the rhythms occurring in : — 



(a) Ovulation. 



(b) Menstruation. 



(c) Coitus. 



(d) Parturition, &c. 



Under 8 (Locomotion) fall, the rhythms connected with walking, swimming, flying, waltzing, &c. 



The recurring, or give-and-take movements witnessed in the inorganic kingdom, which, as explained, are 

 essentially rhythmic in character, are dependent on physical forces, such as gravitation, attraction, repulsion, 

 cohesion, adhesion, condensation, rarefaction, osmose, chemical affinity, &c. 



Examples of rhythms in the inorganic kingdom are to be found in the rise and fall of the tides (give and take 

 of water) ; the alternation of day and night (give and take of light) ; the coming and going of seasons (give and 

 take of light and heat) ; the rise and fall of the barometer (give and take of atmospheric pressure) ; alternations 

 of damp and dryness (give and take of moisture) ; the formation and disintegration of clouds (give and take of 

 the sea, inland lakes, the atmosphere, and the land) ; the appearance and disappearance of frost (give and take 

 of cold and heat) ; the formation of sound and other waves in the air and water (give and take of atoms in a state 

 of vibration) ; the production of calms and winds (give and take of heat and cold equilibrating or producing vacua 

 and air currents), &c.^ 



In order to explain the rhythmic movements which occur in plants and animals, it is necessary to recall and 

 emphasise the fact that all plants and all animals are derived from the inorganic kingdom, and that no element is 

 found in the plant or animal which is not also found in that kingdom. 



It is necessary also to explain, as has been already done, that the elements or substances which enter into the 

 composition of plants and animals carry with them certain forces which inhere in them, and which must be reckoned 

 with as factors, and important factors, in living plants and animals. 



This follows because it has been shown by Professor Helmholtz and others that not only matter but also force 

 is indestructible. 



As it is not possible to destroy matter, neither is it possible to destroy force. The most that can be done is to 

 change the position and form of matter, and to divert the direction of force. There is, it has now been ascertained, 

 a store of matter and of force (physical force) in the universe wliich can neither be increased nor diminished. 



The corollary to all this is, that Uving plants and animals in the processes of growth and development carry into 

 their bodies, by what are virtually rhythmic movements, a large number of the elements which are found in the 

 inorganic kingdom, and also a not inconsiderable portion of the physical forces of that Idngdom, which confer on it 

 its rhythmic and other movements. It was therefore to be expected that the rhythmic movements witnessed in 

 the inorganic kingdom would reappear, in some form or other, in the organic kingdom, and they certainly do. It 

 was also to be expected that the organic rhythmic movements would play quite as definite a role as the inorganic 

 rhythmic movements, and this they hkewise do. As a matter of fact, the organic rhythmic movements are primary 

 or fundamental movements, and are absolutely necessary, not only to the well-being of plants and animals, but also 

 to their very existence. Without them, plants and animals could neither be formed nor maintained. 



The rhythmic movements occurring in plants and animals are spontaneous, independent movements, and 

 neither nerves nor muscles, as they occur in the higher animals, are necessary to their production. It is not possible 

 to explain or get behind the rhythmic movements referred to, and they must be accepted in physics and physiology 

 as ultimate or final. They form parts of a great scheme of movement which pervades all matter, whether living 

 or dead. 



The rhythmic movements may, and do, occur in cells and hving protoplasmic masses in the vegetable and animal 

 kingdoms where no trace of a nervous system or differentiation of any kind can be detected. 



While the cells of plants and animals are endowed with rhythmic movements, not a few of them are provided 

 with cilia or hair-hke processes, which, acting first in one direction and then in another, cause them to move in 

 specific directions. 



Sir James Paget writes : " Probably the simplest example of rhythmic motions yet known is that detected 

 by Professor Busk ^ in Volvox globator. At a certain period of the development of this simplest vegetable 

 organism there appear in each zoospore, or in the bands of protoplasm with which the zoospores are connected, 



' In this enumeration of inorganic rhytlims I do not refer to the manner in which these rhythms are produced. That is a much wider 

 question, and would require separate treatment. 



' " Transactions of the Microscopical Society of London," May 21, 1852. 



