This section is from the book "A Treatise On Beverages or The Complete Practical Bottler", by Charles Herman Sulz. Also available from Amazon: A Treatise On Beverages.
Scientists assert that even the ice with which water is cooled for drinking swarms with disagreeable worms. At a meeting of the French Academy of Natural Sciences, the President, Dr. Joseph Leidy, stated that a member had recently given to him for examination a vial of water obtained by melting ice used for cooling drinking water. The member who submitted the vial had noticed living worms in the sediment of a water cooler, but had supposed that they were contained in the water. Upon melting some of the ice, however, the worms were still observed. These worms, which are the sixteenth of an inch long, and colorless, belong to the same family as the common earth worms. Their bodies have 30 segments bearing spines. Besides this cheerful discovery, Prof. Leidy found in the vial several dead worms, vegetable hairs, and other debris. This state of affairs is not calculated to cause much rejoicing among beverage manufacturers. A filter would have all it could handle to keep even with this water, and no mistake. The idea that water purifies itself by freezing is very prevalent and very deeply rooted. It has led to the use of ice from ponds the water from which no one would think of drinking. Nothing can be more erroneous than this idea. It is true that a few of the solid containants may settle and be eliminated in freezing, but that water once polluted is thus rendered safe is a theory long since exploded. Degrees of cold sufficient to kill disease germs are never experienced in temperate zones. Insects and worms are not infrequently found imbedded in ice. The ice supply of a great city should be subject to as close a scrutiny as the water.