The Austrian physicians came to the conclusion that the Asiatic cholera was of local or terrestrial origin; the facts mentioned above confirm this view to a certain extent, by disproving the general epidemic laws supposed to regulate the progress of cholera and of fever (in which cholera usually terminates), and by showing that the disease sought out, as it were, the inhabitants of certain districts favourable for the production of the deleterious influences I am now about to consider. When the epidemical influence was superadded to these, the disease appeared; its independence of changes in temperature may have been owing to other circumstances not yet investigated. Connected with this evolution of vegetable life in spring and summer, and with its effects on man, is what is called the blooming of plants. The presence of stagnant waters and of foul ditches may be discovered even at a distance by the odour of gases, especially of the sulphuretted hydrogen, they emit. Now, oxygen decomposes this gas, and thus it is not so dangerous as represented to live near waters impregnated with it; but should mud or vegetable refuse be left exposed by the drying up of the waters, this gas ascends wherever the decayed matter is renewed or turned over. Venice, Amsterdam, and other great cities similarly situated, are not unhealthy, although their canals abound with mud; but so soon as the traffic ceases or becomes trifling, a mud odour arises, originating in what the French call _epuration_ or _floraison d’eau_. In every country where there are ponds, canals, or ditches, this vegetable growth takes place so soon as the temperature of the water reaches 60° Fahr. As the quickening of the plants extends from above downwards, from the leaves and stalk towards the roots, these expand, and the mud becomes loosened; the plants imbibe carbon and give out oxygen, and this circulation contributes to the loosening and to the rising of the mud along with the plant. I have witnessed several square yards of mud raised in this way from the bottom of the waters. It subsides, of course, in due time. We have seen that the vital force has no influence upon the combination of the simple elements, as such, into chemical compounds. “No element of itself is capable of serving for the nutrition and development of any part of an animal or vegetable organization;” the vital force by its influence merely combines inferior groups of simple atoms into atoms of a higher order.