IX 3. MEDICAL ASPECTS, 45.a. Water Supply and Sewage Disposal, 45. Possible adverse effects of phytoplanktonic organisms. "Water bloom" in fresh water bodies. "Red tide," "yellow tide," "red snow." Unpleasant odors of water due to phytoplankton. Origin of bad odors and tastes. Mechanism of production. Chemical substances present. Algal oils. Products of photosynthesis. Products of algal decomposition. Death of fish and other aquatic organisms. Oxygenation. Measures to control algal growth. Algal oxidation ponds for sewage treatment. Simplicity and efficiency of oxidation ponds. Algal oxidation to convert nitrogenous wastes into food protein. Radioactivity of phytoplankton in waters near atomic plants. Algae and mosquito control. b. Animal Intoxication, 48. Many reports of animal intoxication and death due to toxic phytoplankton. Table summary of 38 incidents of animal intoxication reported. Confusion with effects of microorganisms, metallic and chemical toxins, and poisonous land plants. Symptomatology varied. Predominance of neuromuscular and respiratory involvement. Photosensitivity. Jaundice. Weakness and paralysis. Convulsions. Dyspnea. Negativity of autopsy studies. Experimental studies. Effects of Microcystis extracts on nervous system, circulation, liver. Degrees of intoxication. Parenchymatous, hydropic, fatty degeneration; necrosis. Studies on toxins. Their chemical and physical natures. c. Human Intoxications, 53. Phytoplanktonic role. Clinical pictures: dysenterial disorders, systemic allergies, local allergic eruptions. Table summary of reported human reactions to phytoplankton. Epidemic intestinal disturbances in U.S. National Parks and West Virginia. Symptomatology. Association with algal bloom in water supply. Systemic allergy to Oscillatoraceae in Wisconsin Lake. Positive skin reactions to Microcystis. Local allergic phenomena. Urticarial "seabathers' eruption." Acute urticaria from "red tide" in Gulf of Mexico. Dermatitis from phycocyanin pigment in Anabaena in Pennsylvania lake. Indirect role of phytoplankton in human disease states. Prototheca and Blastocystis in tropical sprue. Microscopic algae in mycotic skin lesions: actinomycosis, paracoccidiosis. Relation of antibiotic "chlorellin." Antibiotic "phyceine." Antibacterial agents in Stichococcus and Protosypbon. Algae in the diagnosis of death by drowning. Intoxications resulting from ingestion of certain fish. Summary of 58 documented episodes of fish poisoning. Acute "paralytic" shellfish poisoning. Predominantly neurologic manifestations. Epidemiology. Etiology. Relationship to ingestion of toxic Gonyaulax. Nature of toxin in Gonyaulax. Negativity of autopsy findings in acute paralytic shellfish poisoning. Positive findings in chronically poisoned experimental animals. Central nervous system changes. Renal damage. Other toxins from algae. Inherent toxicity of puffer fish and some barracuda. Epidemics of fish poisoning during World War II. Listing of poisonous fish. Clinical classification of ichthyosarcotoxicosis. Tetraodon (puffer) poison...