It is always interesting and also instructive to make comparisons as we progress with our work. To illustrate our meaning let us compare the budding of the yeast plant with the budding of the hydra, which is described in our chapter on pond life. In the same chapter we described the division of a proteus animalcule into two separate organisms, a process which is also undergone by bacteria when circumstances are favourable to their increase. We shall find many points of similarity if we make careful comparisons, and several important differences. Objects for the microscope we can find in plenty, without going far afield. The white mould which we can probably find in the larder, on a pot of jam or other food that has been allowed to stand for some time, will provide a good subject to start upon. A little of this plant, for such it is, carefully lifted on to a dry slide will show the threads of the mould, terminated by round black knobs. Breathe on the specimen and the moisture of your breath will cause these little balls to break and set free a quantity of fine dust-like bodies called spores. The spores will be carried about in the air, they are so light, and if they settle on a suitable medium they will germinate and start another growth of mould. The blue-green mould of cheese is constructed quite differently; its spores are not contained in any hollow structures like those of our first object, but grow in chains radiating from a central point, like the outstretched fingers of the hand. It is this fungus, by the way, which imparts the colour and flavour to gorgonzola cheese.