the skin surface. The deep muscles near 

 the bacxbonehave as.much radioactivity as 



the s.dn surface after 4 days of contact with 

 the soaKed pad. 



Ruthenium -106 



The tests with ruthenium -106 were 

 carried on in a similar manner to those pre- 

 viously described. The pads were soaked in 

 sea water to which had been added ruthenium - 

 rhodium -106 to give a microcurie strength of 

 U . 05 ,uc and . 1 ,uc ruthenium per ml . Un- 

 doubtedly, there was hydration when the 

 material was added to the sea water . The 

 average radioactivity found in the tissues, 

 expressed as percentages of the skin surfaces, 

 is also given in table 2 , 



In these experiments with ruthenium, 

 there was considerable radioactivity at the 

 skin surface from contact with the solution 

 in the pad. However, very little activity 

 entered and the radioactivity of the muscle 

 tissue just under the skin averaged only 11 

 percent of that of the s.cin surface after 8 days 

 of contact with the pads. Muscle tissues 

 deeper than those next to the s.an had virtually 

 no radioactive ruthenium. 



SUMMARY 



1 The radioactive isotopes, strontium -89, 



cesium -137, and ruthenium -106 in sea water 

 in contact with the external surface of pieces 

 of the skin of the little tunny, Euthynnus allet - 

 teratus, pass through to the inner surface. 

 The passage of these elements differs, cesium 

 entering very readily and ruthenium scarcely 

 at all . 



at the skin surface after 4 days in which the 

 isotope was in contact with the sKin . The 

 deep muscles had only 4 percent of the radio- 

 activity of the strontium -89 of the skin sur- 

 faces after 8 days of contact of the skin with 

 this isotope. These tissues had 1 percent of 

 the ruthenium -106 radioactivity of the skin 

 surface after 8 days of contact. 



LITERATURE CITED 



BOND, RICHARD M 



1933 . A contribution to the study of the 

 natural food cycle in aquatic 

 environments, with particular 

 consideration of micro-organisms 

 and dissolved organic matter. 

 Bull Bingham Ocean. Collection, 

 vol, 4, art. 4, pp. 1-89. 



GODSIL, H. C. 



1940. Conclusion and summary of De- 

 tailed Progress Report No. 2 

 on the refrigeration of tuna. 

 Calif Div. of Fish and Game, 

 Mimeographed Report (July 15, 1940) . 



HOLSTON, J . , and S . R POTTINGER 



1954. Freezing fish at sea - New England. 

 Part 8 - Some factors affecting the 

 salt (sodium chloride) content of 

 haddock during brine -freezing and 

 v/ater -thawing. Comm. Fish. Rev., 

 vol . 16, no. 8, pp. 1-11 . 



LAND, O.W., andL. FARBER 



1939. The preservation of tuna by chilled 

 brines: A progress report. 

 Proc . Sixth Pacific Sci. Congress, 

 vol. 3, pp. 281-289. 



2 When these isotopes are in contact with 



the skin of iced tunny, they enter and diffuse 

 into the muscle tissues beneath. Except for 

 cesium, diffusion through the fish tissues is 

 slow. The cesium- 137 content of even the 

 deep muscle tissue was equal to the amount 



WUNDER, WILHELM 



1936. Physiologic der SUsswasserfische 

 Mitteleuropas. Reprinted from 

 Handbuch der Binnenfischerei 

 Mitteleuropas, vol. II -B: Stuttgart. 

 340 pp. 



