The injurious effects of water holding such substances, gaseous and solid, in solution, we overcome by boiling and passing the steam through (heated) iron pipes, and re-converting the steam into water. By this process we get rid of the injurious effects of these foreign matters, gaseous and solid, held in a kind of solution by the water, in as far, at least, as they affect the colours used in dyeing. During these examinations of the waters themselves, it was distinctly observed that the infusoria and testaceous mollusca, microscopic and otherwise, with which such waters abound, were developed in glutinous membranes attached to the aquatic herbs abounding in these waters; in short, these membranes seem to be the matrix for the growth, nourishment, and production (using the term in a limited sense) of these organized beings; they form an essential condition of their existence. The plants themselves were now washed in distilled water, and the animal products were the semivalve and bivalve shells of which I have preserved many specimens. The semivalve belong to the natural families Buccinum, Lynceus, Helix, and Planorbis; the bivalve to the Cardiacæ. The semivalves are the most abundant. By filtering the water which remained after the shells had been removed, innumerable minute particles like dust were discovered; these particles were ascertained by the aid of the microscope to be mainly composed of minute fragments of aquatic plants and of the spores of fungi; to these must, no doubt, be added, although not visible when dried, the remains of zoophytes, and of the glutinous membranes forming the matrix of animal aquatic life. I now endeavoured to obtain the glutinous membrane or matrix in which these testaceous mollusca were obviously developed, apart and distinct from the animals themselves. To attain this desirable point we filled a glass receiver with water containing the aquatic plants and shells, and the gelatinous membrane already spoken of. The receiver was now inverted upon a plate, and water poured into the plate to the depth of half an inch. In a few days the receiver became filled with gas, forcing the water downwards into the plate on which the receiver rested; and although after the first day we could not discover any of the gelatinous membranes in the lower part of the receiver, yet that in the plate became like a flaky jelly, attaching itself to blades of grass or leaves. The surface exposed to the atmosphere became dry and brittle, and in this state resembled thin layers of gum; the substance thus desiccated strongly resembled jelly.