Do you know the _Utricularia_? I will devote the next chapter to these curious plants, and to the microscopic animals which they capture. It will take a little practice to learn where and how to collect material for the microscope. We should not depend too much upon books in any branch of natural history. To be successful, you must observe for yourselves, experiment and examine independently, consulting books that you may name and classify, that you may recognize and name what you find. If you fail to find specimens in one spot, try another. You should not fill your collecting bottles more than two thirds full of water, nor crowd too many plants in them. These little creatures must have air in order to live, as well as the higher animals. [Illustration: FIG. 2.] The finest tree-vorticellas I ever found were in Florida, in the St. John's River. These trees were attached to long, floating stems of _Myriophillum verticillatum_, and were unlike any species that I ever found at the North. They were very large--in a microscopic sense--plainly visible to the naked eye, and it took only a moderate power to bring out their beauty. _Vorticella nebulifera_ is quite common in swamps and ponds. We find it attached to a great number of water plants. This species is not built up in the form of a tree, but it is nevertheless beautiful and graceful. The delicate, slender stems start from a node, or rounded mass, sometimes fifty or more of these fairy like creatures in one colony, all attached to a common centre, swaying about, coiling their delicate transparent stems, and again uncoiling quick as a flash, apparently dallying and playing, but never interfering nor becoming entangled one with another. The _Stentor_ is another member of the _Vorticellinae_ family. It is one of the largest of the infusoria, plainly visible to the naked eye, and one of the most interesting and curious of all the strange animals in the microscopic world. It assumes various forms. When swimming, it looks round and plump (_Fig. 2_), and rushes through the water pell-mell, knocking the smaller animals right and left, always seeming to be in a great hurry, unless two friendly ones happen to meet, when they frequently stop and put their heads together a moment as if exchanging greetings, then away they sail again, dashing through the water, capturing and devouring the smaller creatures as they go. And now a couple meet that are very communicative--two gossips, no doubt! At all events, they put their heads together and conclude to have a good sociable time. And they are sensible enough to know that they cannot stand around loose in the water or public highway. So they select a cosey spot and fasten their feet to a plant or some firm object, and stretch out their footstalks sometimes to a great length, making veritable trumpets of themselves. (_Fig. 3._)