pains developed, and gradually the other symptoms. He required no other 

 treatment than bed rest at home. Jaundice cleared after 10 days and health 

 returned in 3 wks . Two of the other friends developed jaundice and con- 

 currently underwent similar episodes. Family contacts received immune serum 

 globulin prophylaxis, and no secondary cases developed. Steaming clams 

 produces internal temps below what is necessary to inactivate the hepatitis 

 virus. This accidental in vivo experiment, especially in conjunction with 

 other cases, demonstrates that steamed clams may indeed transmit hepatitis. 

 - J.L.M. and M.W.S. 



569 



Feng, S. Y. 1966. 



Biological aspects of hard clam purification. Proc. Natl. Shellf. Assn. 

 56: 3 (abstract). 



Clam activity is affected by temp and salinity and may be increased by 

 addition of organic materials such as glucose. Laboratory populations had 

 a definite diurnal cycle of activity. Activity of clams may be increased 

 by manipulation of light. In all studies some Mercenaria mercenaria were 

 inactive for several days, which could affect a purification procedure. 

 At lower temps (5°C) clams are more likely to retain viral particles. 

 Viruses are not completely eliminated or destroyed when seawater is 

 changed repeatedly or treated with ultraviolet light, or both. - J.L.M. 



570 



Feng, S. Y. 1967. 



Further studies in clam depuration. Proc. Natl. Shellf. Assn. 57:2 (abstract) 



In a study of elimination of viral particles by hard clams, Mercenaria 

 mercenaria, two bacteriophages, Staphylococcus aureus phage 80 and 

 Escherichia coli phage S-13, were used as virus models. Hard clams 

 experimentally contaminated with the two phages were treated in re- 

 circulating and flow-through seawater systems. Seawater, ranging from 

 20 to 22°/°° salinity, was irradiated by UV light before reaching clams. 

 Experiments were carried out from 10° to 20°C and flow rates from 50 to 

 150 gallons per hour. Purification rates of the two bacteriophages by 

 hard clams were independent of temperatures (10°, 12°, 15°, 18°, and 20°C) 

 and flow rates (50, 100, and 150 gallons per hour). Elimination is 

 characteristically an initial rapid removal followed by a more gradual, 

 6-day attrition of viral particles. Clams apparently eliminate the two 

 bacteriophages at different rates: S. aureus phage 80, the less hardy of 

 the two, is eliminated much faster than is E. coli phage S-13 which re- 

 sembles poliomyelitis virus in size, shape, and nucleic acid content. - D.L. 



571 



Feng, S. Y'. 1969. 



Responses of some estuarine bivalves to temperature and salinity changes. 

 In Proc. Conf. on Shellf. Culture. Nassau-Suffolk Regional Marine 

 Resources Council, p. 49-57. 



(Abstracter's note: Much of this paper is a valuable review of the 

 literature on the subject. Details are contained in other abstracts in 

 this compendium. Only previously unreported studies by Feng are contained 

 in. the following abstract.) Osmotic concentration of body fluids in hard 

 clam tends to remain high as external medium is diluted. Closing of shell 

 gives temporary protection by decreasing permeability. Hard clams were 

 held in water ranging in salinity from to 40°/°° for 24 hours. From 

 to 20°/ O o shells remained tightly closed. Above 20°/oo clams extended the 

 siphon. Internal osmotic concentrations were isotonic at 28°/°o or 

 slightly hypotonic (at 39°/°°) to the external medium. A figure is 

 presented to give a quick visual concept of the combined effects of 

 temperature and salinity on development of eggs and survival and growth 

 of larvae of hard clam. Information on responses to pollutants, thermal 

 and osmotic and other stresses, is needed to evaluate ecological con- 

 sequences of altered natural conditions, assessing immediate and long-term 

 effects on shellfishes, and providing sound countermeasures. - J.L.M. 



160 



