300 DESIGN IN NATURE 



plant, according to others an animal, and according to a third, a half plant or a half animal. ^ This raises a question 

 of primary importance in physiology and psychology. Is it necessary to believe that organisms devoid of a nervous 

 system, or, at all events, of a tangible nervous system, are hopelessly ignorant of their own existence, seeing they 

 can move in definite directions and shape their ends ? Further, are the lower animal forms (say the five-rayed star- 

 fish), which are provided with gangha and sensory and motor nerves, but no brain, and whose movements are 

 undoubtedly voluntary, devoid of the conscious ego ? 



The brain of the centipede consists of a sUght differentiation and increase of two of a longitudinal chain of 

 gangha which occupies a central dorsal position in the body of the creature, and similar remarks may be made of 

 the brain even of man. There is in man a striking augmentation of brain substance and brain difierentiation, but 

 there is no breach of structural continuity as between the brain and the spinal cord, and no difference in the nature 

 of the nervous matter ; it is a mere question of increase, elaboration, and differentiation. There is, in short, not 

 a difference of kind, but only of degree, in nervous matter. The same is to be said of nervous and psychical 

 manifestations in the lowest and highest animals. 



If, however, protoplasm can assume every variety of form and movement as apart from a tangible nervous 

 system, it requires no great stretch of the imagination to believe that a nervous system, in the absence of a brain, 

 discharges the essential functions of a brain ; the brain being simply a more highly developed and elaborated portion 

 of the nervous system proper. In the lancelet {Amfhioxus lanceolatus), the lowest of the " vertebrates," there is a 

 spinal cord but no brain (Goodsir, 1841). 



This line of argument militates against the exclusive possession of intellectual faculties and mind by man ; 

 but, on the other hand, it accounts for a large number of facts otherwise inexphcable, namely, the voluntary and, 

 it may be, conscious acts of the whole animal series provided with nervous systems, from man downwards. It is 

 well known that the monkey, elephant, dog, horse, and a large number of quadrupeds reason. Similar remarks 

 may be made of birds, and, within limits, of reptiles, fishes, spiders, ants, bees, &c. In all these cases it is mere 

 assumption to assert that the individual is non-conscious. The words instinct, unconscious cerebration, and reflex 

 action, do not explain the phenomena witnessed. 



The fact that the insectivorous plants can, by concerted, co-ordinated movements, catch insects, and digest, 

 absorb, and assimilate them ; while the Mycetozoa can advance in search of food and retrace its steps and con- 

 centrate on food when found, and digest and assimilate it, have further to be explained. Two explanations can 

 be given : either the Creator works directly upon and through plants and the lower and higher animals, or aU these 

 are provided with structures and endowments which, potentially, are equal to all the requirements of hfe, whether 

 these be physical, mental, or psychical. 



The Mycetozoa have been studied to good purpose by Mr. Arthur Lister, who has skilfully summarised our 

 knowledge of these interesting forms. He says : — 



" They are characterised by the constant sequence of three main stages in their hfe history : — 



"1. The firm-walled spore gives birth to a swarm-cell. 



"2. The swarm-cells coalesce to form a wandering plasmodium. 



" 3. The Plasmodium ultimately concentrates to form either sporangia, enclosing numerous spores (Endosporese), 

 or sforofhores bearing spores on their outer surface (Exosporese). 



" Many species are quite common, and are found on old decaying stumps of trees and fallen branches in moist 

 woods and shaded gardens ; others inhabit heaps of dried leaves which have lain undisturbed and become soaked 

 with rain. The only stage in which they are conspicuous is that of the sporangia, when they appear as minute 

 objects, some roundish, about the size of small mustard seeds, others rising in clusters of brown columns on black, 

 hair-like stalks, while many take other characteristic forms. The different species display great variety and beauty 

 in the colours they assume, ranging from pure white, golden yellow, bright crimson, and iridescent violet to dark 

 purple and black. 



" The various phases in the life history of the group may be described as follows. The swarm-cells emerge from 

 the spores as amoeboid bodies ; they soon acquire a flagellum at the anterior end, and creep in a linear form with 

 the flagellum extended in advance, or swim in the surrounding water with a dancing motion occasioned by the lashing 

 movement of the flagellum. They possess a single nucleus and a contractile vacuole. To a large extent the swarm- 

 cells of Mycetozoa feed on bacteria, which are caught by fseudofodia projected from the posterior end of the body. 

 The bacteria are conveyed into the body-substance, where they are digested in vacuoles which form round them. 

 There may be one or more digestive vacuoles, each containing several bacteria at one time. The swarm-cells rapidly 



1 Mr. Saville Kent supports the auimality view, and traces a connection between the Mycetozoa and the Spongidte ; tlie resemblance extending 

 to the fission or aniceliic stage, to the production in both of spoi'es with flagella or cilia of some kind, to the encysted or resting hibernating 

 condition, and to the presence in both of rudimentary skeletons in the sha])e of horn-like elements or keratose, and spicule-like bodies of carbonate 

 of lime. 



