mucous layer (the stratum mucosum of botanists), does not constitute the organs of the animalcules, though the latter cannot live and propagate themselves but in the middle of them. Nevertheless, I have often drawn them out of the gelatinous mass, in order to place them in river-water, where they lived a long time, without any appearance of diseased alteration.
Water, a solid substance, heat, a beginning putrefaction, appear indispensable to the production and propagation of the animalcules; and such conditions are in fact always united. Without moisture, they never live; a solid substance must offer a basis to moisture, and, according to physical laws, the contact of the one with the other generates heat, and only by the simultaneous action of moisture and heat can putrefaction take place.
Though often found in the froth of rivulets and rivers, they have not been generated there, but floated off by the stream. These animalcules living never in thermal water, they are only to be seen at a few inches distance from the wells, and when kept in glasses or pots, they soon retreat towards the sides of the vessel. They are never found in the limpid water of a cold spring, river or well, nor of a hot spring, even if the water has reposed for hours and days, so that we can consider as erroneous, and suggested by a fondness for marvellous things, the popular opinion, so generally spread, that we swallow with common water innumerable
