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BULIvETIN of The bureau of fisheries. 
and bottom of the jar, or, in the case of the lighter more oily portions, floated on the 
surface of the water, none, or very little of it, was removed while the water flowed through 
the siphons. The water, therefore, was almost completely changed without removing 
the tar. Shortly after the water had been changed the oyster was seen to be slightly 
open, but could close at the slightest jar. The water was changed in this manner once 
or twice daily for lo days, The oyster was often seen partly open during this time, 
but would always respond to a mechanical stimulus by closing. After lo days the 
water was no longer changed, but was left entirely stagnant. At the end of two weeks 
under these conditions the oyster seemed to be affected. It now remained continuously 
open, and appeared unable to close when stimulated. A few days later it showed signs 
of putrefactive disintegration. 
Experiment 2 . — An oyster weighing 63.7 grams was treated exactly as in experi- 
ment I . The results were quite the same, except that when the water was left entirely 
stagnant disintegration set in after five days. 
Experiment 5. — An oyster weighing 71.6 grams was treated as in the preceding 
experiments, except that the tar was smeared all over the inside of the jar and on the 
oysters. After 24 hours the oyster was found wide open and unable to close when 
stimulated. It was removed from the jar, and was seen to have its mantle greatly 
retracted. It would spring open when closed by hand. It was washed and put into an 
aquarium in running sea water. Two days later it appeared to be entirely recovered, 
as it would close normally when stimulated. It was then put back into the jar of sea 
water and tar in which it had been at first. It was now kept in this jar during six days, 
with the water changed once or twice daily. At the end of this time it had again lost 
the ability to close normally, but when put in the aquarium once more it again appar- 
ently recovered. About three weeks later, however, it became disintegrated. 
Experiment 4 . — An oyster weighing 95 grams was arranged exactly as in experi- 
ment 3. The results were quite the same, that is, after 24 hours it refused to close, 
but recovered when put in the aquarium of running sea water. Some weeks later, 
however, it died. That its death was due to the tar is not certain, because at that time 
other oysters in the same aquarium died without any previous exposure to tar. 
Experiment 5. — An oyster weighing 78.7 grams was treated exactly as in the preced- 
ing experiment. It, too, became unable to close after 24 hours, and when put in run- 
ning sea water entirely recovered. At the end of the summer, nine weeks later, it 
seemed entirely normal and had a normal appearance when opened. 
Experiment 6 . — An oyster weighing 62 grams was treated exactly as in the preced- 
ing experiment. The result was slightly different in that the oyster did not begin to 
show a tendency to remain open until after three days, and became entirely unable to 
close after five days in the tarry water with daily changing of the water. It was then 
put in running sea water and began to disintegrate a few days later. 
Experiment 7. — An oyster weighing 70.8 grams was put into a battery jar with 20 
c. c. of the tar not in contact with it and 2,500 c. c. of sea water. The water was changed 
daily during the next 10 days. It was then left stagnant during 8 weeks. The oyster 
was sometimes observed to be open, but would then close if jarred. At the end of that 
