“The apparent function of the Diatomacae in the economy nature, viz. to vivify, as it were, the immensity of the ocean, as well as all fresh and brackish waters, decomposing, as they do, carbonic acid under the influence of light, and consequently giving off oxygen, is sufficient to show that organisms of such excessive minuteness must be endowed with an extraordinary reproductive capacity in order to supply, by their number, the vast scope of the office they are destined to fulfil.”