MICHOSCOPE IX THE GARDEN. 45 



the cells, or the movements will not be seen. This 

 movement seems dependent on the internal proto- 

 plasmic matter, or " primordial utricle," which is 

 contained in many cells, and which, in these cases, 

 is spread over the interior of the cell. It is, how- 

 ever, capable of contraction, and when the plants 

 are exposed to cold, the utricles contract and pre- 

 vent the movement of the contents in the interior. 

 It is, apparently, the extension of this substance 

 beyond the walls of the cell which constitutes the 

 little hairlike organs called " cilia," which are con- 

 stantly moving, and by the aid of which the spores 

 of some plants effect rapid movements. Such 

 organs are found in the Pandorina Morum and 

 Volvox globator, moveable plants represented at 

 figures 13 and 14, plate 1. The effect of these 

 cilia in producing the movements of plants is well 

 seen in the Volvox globator, which, on account of 

 its rapid movements, was at one time regarded as 

 an animalcule, but it is now regarded as a plant. 

 Cilia are, however, more frequently met with in the 

 animal kingdom. They are seen in the drawing of 

 Plumatella repens, at a, in figure 163 of plate 6. 



Amongst the parts of plants which can alone 

 be investigated by the Microscope are the stamens. 

 These organs are situated in the flower, between 

 the petals and the pistil, and usually consist of a 

 filament, or stalk, with a knob or anther at its top. 

 If the anther is examined, it will usually be found 

 to consist of two separate valves, or cases, in each 

 of which is contained a quantity of powder, or dust, 

 called " pollen." The walls of these valves are 

 worth careful examination under the Microscope, 

 on account of the beautifully-marked cellular tissue 

 of which their inner walls consist. The cells of this 

 tissue contain in their interior spiral fibres similar 

 to those which have been described as present in 



