20 



BULLETIN 740, U. S. DEPARTMENT OF AGRICULTURE. 



From Table 6 it is apparent that oysters lose a marked proportion 

 of their total solids, and therefore their nutritive value, during the 

 process of washing. In speaking of these losses the following terms 

 are used : 



(a) " Apparent loss", denotes the entire loss shown by the analysis. 

 This loss is due to both osmotic distention and solution or 

 suspension in the wash water. 

 " Osmotic loss" denotes the loss due to osmotic distention of the 

 tissues of the oysters. This is not an actual loss of sub- 

 stance, but a replacement by an equal amount of water. 

 " Actual loss" denotes the loss caused by solution or suspension of 

 part of the oyster substance in the wash water. This loss 

 is actual, as the substance thus dissolved or suspended goes 

 to waste. 

 These losses have been calculated for the more important experi- 

 ments, using as a basis the amount of each substance present in the 

 shucked stock. The figures are tabulated in Table 7. 



(6) 



(c) 



Table 7. — Losses ex 



percentages of original amounts present. 



Experi- 

 ment No. 



Figure 



of 



osmosis. 1 



Amino-acid nitrogen. 



Total solids. 



Ash. 



Appar- 

 ent. 2 



Os- 

 motic 3 



Actual. * 



Appar- 

 ent. 2 



Os- 

 motic. 3 



Actual/ 



Appar- 

 ent. 2 



Os- 

 motic. 3 



Actual. 4 



3 



Percent. 

 78.3 



100.0 

 80.0 

 81.8 

 81.4 

 81.5 

 85.0 

 79.0 

 70.6 

 67.8 

 82.2 

 73.7 



100.0 

 92.0 

 82.7 



Per cent. 

 27.0 

 None. 

 24.6 

 36.0 

 40.8 

 30.5 

 59.4 

 35.3 

 47.3 

 48.7 

 30.8 

 37.0 

 7.8 

 25.2 

 28.1 



Per cent. 

 21.7 



None. 

 20.0 

 18.2 

 18.6 

 18.5 

 15.0 

 21.0 

 29.4 

 32.2 

 17.8 

 26.3 



None. 

 8.0 

 17.3 



Percent. 



5.3 

 None. 



4.6 

 17.8 

 22.2 

 12.0 

 44.4 

 14.3 

 17.9 

 16.5 

 13.0 

 10.7 



7.8 

 17.2 

 10.8 



Per cent. 



40.9 



5.6 



Per cent. 

 21.7 



None. 



Per cent. 



19.2 



5.6 



Percent. 



. 47.7 



27.6 



Percent. 



21.7 



None. 



Percent. 

 26.0 



4 



5 



27.6 



7 



30.4 

 33.0 

 23.4 

 34.7 

 23.5 

 30.5 

 33.6 

 29.5 

 30.6 

 4.7 

 20.0 

 23.8 



18.2 

 18.6 

 18.5 

 15.0 

 21.0 

 29.4 

 32.2 

 17.8 

 26.3 

 None. 

 8.0 

 17.3 



12.2 



14.4 

 4.9 



19.7 

 2.5 

 1.1 

 1.4 



11.7 

 4.3 

 4.7 



12.0 

 6.5 



41.4 

 63.8 

 51.8 

 69.2 

 52.3 

 63.8 

 64.2 



18.2 

 18.6 

 18.5 

 15.0 

 21.0 

 29.4 

 32.2 



23.2 



8 



45.2 



9-A 



9-B 



10-A 



10-B 



10-C 



11 



33.3 

 54.2 

 31.3 

 35.4 

 32.0 



12 



56.4 

 8.5 

 53.0 



26.3 



None. 



8.0 



17.3 



30.1 



13.. .. 



8.5 



14 



45.0 



15 



34.2 















17.60 



14.30 





17.46 



8.59 





17. 46 32. 77 

















1 Percentage of original amount of each substance which would be present if the apparent loss were due 

 to osmosis alone. 



2 The entire loss shown by analysis. This loss is due to both osmotic distension and solution or suspen- 

 sion in the wash water. 



3 The loss due to osmotic distension of the tissues of the oysters. This is not an actual loss of substance, 

 but a replacement by an equal amount of water. 



4 The loss caused by solution or suspension of part of the oyster substance in the wash water. This loss 

 is actual, as the substance thus dissolved or suspended is washed off and goes to waste. 



Experiment 8. — Taking the amount of each substance present in 

 the shucked stock as 100 per cent for a basis of calculation, it is 

 seen that if the decrease in percentage of the various substances 

 were due to osmotic distention alone each of these substances would 

 have a value of 78.3 per cent at the end of the process, since the 

 volume of the oysters increased from 90.86 liters to 116.06 liters. 

 The actual figures obtained, however, are as follows: Total solids, 73 



