physiological routes by which compounds affect 

 fish is shown in table 1 where most unrelated 

 groups of chemicals included one or more toxic 

 compounds . 



Despite the "confusion" resulting from 

 lack of knowledge of the chemicals and their 

 effects on carp, certain figures and relations 

 pertaining to toxicity did appear. These are 

 probably unimportant to the fields of toxicity, 

 chemistry, and physiology but may be of inter- 

 est to those contemplating screening programs 

 of their own . 



Of the 1,496 chemicals presented in table 

 1 , only 7 percent killed all three of the fish that 

 were initially fed large doses. This is typical 

 of a screening program employing randomly 

 selected compounds. Chemicals received from 

 companies that made an effort at selection killed 

 a slightly higher percentage of fish. 



Certain large groups of compounds showed 

 a high degree of biological activity and included 

 the aliphatic phosphates, amine salts and phenols, 

 the heterocyclic alkaloids, and the inorganic halo- 

 gens. Groups showing little biological activity 

 included the aliphatic carboxylates, carbamates, 

 carbanilates , metal amine complexes, sulfides, 

 and disulfides, and the aromatic hydrocarbons, 

 esters, ethers, and amines. Very few chemicals 

 killed fish at very low doses of 10 milligrams per 

 kilogram or less. 



A number of compounds that have been 

 widely used as insecticides or rodenticides 

 produced little or no acute effect when force -fed 

 to carp . From the publicity these compounds 

 have received and the furor often resulting from 

 their improper use one would expect them to have 

 some acute effect on carp. They include pure 

 toxaphene, the DDT derivatives including DDT 

 and methoxychlor , warfarin, lindane, aldrin, 

 heptachlor, chlordane, dieldrin, pure Thiodan, 

 parathion, and arsenic trioxide. 



The great majority of lethal compounds 

 produced only the vaguest of symptoms. Gener- 

 ally speaking, fish become sluggish over a period 

 of time which varied considerably depending upon 

 fish, chemical, and dose. Toward the end of 

 the test period the fish turned on their sides 



either at the surface of the water or the tank 

 bottom and died. Movements during the period 

 when the fish were affected can only be described 

 as random. None of the 1,496 chemicals pro- 

 duced surfacing (as caused by certain derivatives 

 of d-lysergic acid; (Loeb, 1962), or any positive 

 directional movement that could be detected. 



A few chemicals did produce positive 

 symptoms . Three chemicals popularly regarded 

 as chlorinated hydrocarbons caused alternating 

 and long-lasting periods of irritable, erratic, 

 and relatively normal swimming patterns . They 

 were toxaphene (60.5 percent miscible), endrin, 

 and Thiodan. Most lethal aliphatic phosphates 

 caused noticeable paralysis and color changes . 

 A few other chemicals also produced recogniz- 

 able symptoms. Ephedrine, for example, caused 

 a color loss that lasted for weeks. 



Since the force-fed fish were not held for 

 more than a few days for observation, the effects 

 presented in this paper must be judged as acute 

 or immediate. It is entirely possible that single 

 doses of some of the chemicals would produce 

 chronic symptoms, but such observations were 

 beyond the scope of this study. 



ACKNOWLEDGMENTS 



The force -feeding program would not have 

 been possible without the cooperation of many 

 chemical companies, the United States Depart- 

 ment of Agriculture, and Cornell University. 

 These agencies (table 3) assembled and shipped 

 chemicals (sometimes specially formulated for 

 the project) free of charge for screening. 



John F. LesVeaux of the Research De- 

 partment of the Niagara Chemical Division, Food 

 Machinery and Chemical Corporation, and Drs. 

 Edwin E. I>ann and Clarence L. Moyle of the 

 Biochemical Research Laboratory, Dow Chemical 

 Company, provided considerable advice pertain- 

 ing to handling of chemicals and screening methods , 



The chemical abstracting and classifying 

 of compounds was done by Dr. Emil J. Moriconi 

 of Fordham University. 



Kenneth F . Stafford of the Fish Laboratory 

 demonstrated exceptional initiative in providing 



