. The cell; outlines of general anatomy and physiology. oa and Radiolaria, whilst g is taken from LehmannsMolecular Physics, and represents a drop of creasote in water, inwhich it has assumed a form resembling a typical Actinosphzerium(Verworn III. 24, p. 47). Other attempts to explain the protoplasmic movements (Engel-mann III. 6, Hofmeister II. 20, Sachs) lead us into the domainof theories upon the molecular structure of organised bodies, sincethe cause of the movements is supposed to lie in the changes ofform of the most minute particles. A discussion of Verwornslatest attempt (III. 24) wou
. The cell; outlines of general anatomy and physiology. oa and Radiolaria, whilst g is taken from LehmannsMolecular Physics, and represents a drop of creasote in water, inwhich it has assumed a form resembling a typical Actinosphzerium(Verworn III. 24, p. 47). Other attempts to explain the protoplasmic movements (Engel-mann III. 6, Hofmeister II. 20, Sachs) lead us into the domainof theories upon the molecular structure of organised bodies, sincethe cause of the movements is supposed to lie in the changes ofform of the most minute particles. A discussion of Verwornslatest attempt (III. 24) would lead us too far in another direction. THE VITAL PROPERTIES OF THE CELL 77 Once for all, it must be admitted that none of the hypotheseswhich have, up till now, been propounded, are able to furnish uswith a satisfactory conception of the causes and mechanical con-ditions of the plasmic movements, and that, therefore, we mustconfine ourselves to a simple description of observed , however, is not to be wondered at, when we consider what. Fig. 42.—Different appearances assumed by drops of oil, which have spread themselvesout. (After Verworn, Fig. 11.) a number of different opinions are held with regard to the ultimatestructure of protoplasm itself (see pp. 18-26), and this must ofcourse affect the explanations tendered of its movements. II. Movements of Flagella and Cilia. Unicellular organ-isms, by means of their flagella and cilia, are able to move from 78 THE CELL place to place much more rapidly than can be effected by meansof pseudopodia. Flagella and cilia are delicate hair-like processes,which extend in greater or less numbers from the surface of thecell. They are composed of a homogeneous, non-granular sub-stance, and in this respect resemble short, thin pseudopodia,when these consist of hyaloplasm alone. However, they differfrom pseudopodia in two respects : firstly, they move in a differentand more energetic fashion, and secondly, they are not transito
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