The purpose of the experiment was to see if toxic material that 

 may be present at very great dilution has any effect on Tubularia if 

 the organism is removed from the immediate vicinity of the oil. 



Only the crude oil and Diesel oil, either alone or mixed with 

 carbonized sand, were employed in these tests. The results summarized 

 in tables 8 and 9 show that under the conditions of the tests no ill 

 effect on Tubularia became apparent during the two and one-half days 

 of exposure to either type of oil. The test was discontinued at this 

 time because of the marked mortality of Tubularia in the control 

 (table 8). 



We infer from these experiments that Tubularia suffered no ill 

 effects from oil, pres\anably becatise no sufficient concentration of 

 the toxic material was built up in the running water and the organism 

 was removed from the immediate vicinity of the oil. 



In the second series of tests lumps of c8U"bonized sand and crude 

 oil were placed in the immediate vicinity of the colony of Tubularia, 

 which were kept in glass battery jars of 2-liter capacity. The sea 

 water was kept running through the jars at a rate of 30 liters per 

 hour. In the first test, tiie water from the control jar, containing 

 69 hydranths, was siphoned to the experimental jar, with 78 hydranths, 

 A mixture of 2,5 ml, of crude oil and 7 grams of carbonized sand was 

 placed on bottoni close to the. colony, but not touching it, Dia-ing 

 the five days (120 hours) this test was continued the temperature of 

 water fluctuated between 19.8° and 20,4° C» At the end of the test 

 all the hydranths in the control were alive. In the jar containing 

 oil and sand mixture, the first morteility was observed after 48 hours, 

 when 22 hydranths were found dead and were removed. By the end of the 

 fifth day, 35 additional hydranths died, 15 were alive and 6 were not 

 accounted for, apparently having been carried away by the stream. 



In another test sea water was supplied directly to each of five 

 battery jars, one of which served as control. On the bottom of four 

 were placed respectively 5 ml,, 10 ml,, 20 ml., and 30 ml, of crude 

 oil with appropriate amounts of carbonized sand. The rate of flow 

 through each jar was increased over that of the first experiment and 

 kept between 65 and 75 liters per hour. From 50 to 61 Tubularia were 

 placed in each jar. The temperature varied between 20,4° and 20,7° C« 

 At the end of the fifth day there was a noticeable mortality in the 

 control jar (30 hydranths died out of original 50) but a much more 

 marked loss occurred in all the experimental jars (table 10). It is 

 interesting to note that within the first 48 hours there was no death 

 of hydranths in the control end relatively insignificant loss (9 out 

 of 53) in the jeur containing 5 ml, of oil. 



14 



