14 BULLETIN 740, U. S. DEPARTMENT OF AGRICULTURE. 



morning. In all these tables allowance has been made for all samples 

 removed. Due to the fact that the oysters settled to the bottom of 

 the tank and formed a compact mass which was almost impervious 

 to water, very little opportunity was offered for osmotic action to 

 take place, and the volume of the oysters remained practically con- 

 stant throughout the experiment. In the periods of disturbance, 

 however, which occurred while the oysters were being measured and 

 the water was being removed fresh water came into contact with the 

 oysters, and some of it remained with them in the bottom. Thus, 

 a little osmotic action other than that at the top of the mass took 

 place, and solution progressed continuously, though somewhat slowly. 

 Since the volume remained practically constant throughout this exper- 

 iment, it is evident that all the loss observed in this case must be due 

 to solution or mechanical loss. In this case mechanical loss was 

 small. In commercial pratice oysters never are subjected to such 

 long continued action of water, but this experiment proves that a 

 large percentage of the substance of the oyster is soluble in fresh 

 water, and that osmotic distention is negligible in oysters washed 

 in a tank without agitation. As is to be expected, the purely soluble 

 constituents show a much more marked decrease than do the total 

 solids, which include both soluble and insoluble substances. 



Experiment 2. — This experiment was carried out in the same way 

 as was Experiment 1, with the same purpose in view. On the third 

 day, however, the samples were taken from the bottom of the tank 

 instead of from a representative sample of the whole, as was usually 

 done, in order to determine whether or not the bottom oysters were 

 being affected by the water. The results show very clearly that 

 they were not being so affected, as the percentages of total solids, etc., 

 did not change during 24 hours of soaking. The percentages show 

 the same relative decrease as in Experiment 1. 



Experiment 3. — Having established the fact that a marked pro- 

 portion of the solid substance of the oyster is soluble in fresh water, 

 it becomes desirable to discover what proportion of the apparent 

 loss of the various substances is due to actual loss in the wash water, 

 and what is due to the increase in volume of the oyster. In this 

 experiment, 20 gallons of oysters were taken from the chute imme- 

 diately before entering the agitation tank, carefully measured into 

 one of the tanks, and washed in the regular way, except that the 

 washing was continued for one hour. Samples were taken before 

 the process was started and at 15-minute intervals during washing. 

 Detailed discussion of this and following experiments will be taken 

 up later in connection with Table 7. 



Experiment 4- — This experiment was conducted in an oysterhouse 

 in which . the old system of washing was used. Five gallons of 

 shucked oysters were measured out and placed upon the skimmer. 



