808 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 
per cent, of the total weight. The liquids showed in one case in 
increase from 5.51 to 5.76 per cent., and in the other a decrease from 7.78 
to 6.48 per cent. This disparity, however, is not to be wondered at when 
we consider that the liquids are very little affected by the dialysis, but 
are doubtless swept away by the surrounding water to greater or less 
extent in proportion as the valves are more or less opened and the cur- 
rent is stronger or weaker. 
The figures for the composition of the flesh show more exactly how 
the gain in quantity is brought about by gain of water. The water in 
the flesh increases in one case from 78.0 to 82.8, and in the other from 
77.9 to 82.1 per cent., the percentages of water-free substance decreas- 
ing, of course, in corresponding, degree during the dialysis. The varia- 
tions in the several ingredients will appear more clearly if we compute 
the increase or decrease of each in per cent, of its own percentage in 
the flesh before the osmose. 
For example, flesh of the James River oysters contained before the 
dialysis 10.63 per cent, of protein (N x 6.25), and after dialysis 8.79 per 
cent. The difference (10.69— 8.79) is 1.84 per cent. This difference, 1.84, 
is 17.3 per cent, of 10.63, the percentage of protein in the flesh before 
dialysis. In other words, the protein has fallen off 17.3 per cent, of its 
amount before dialysis. The proportions of the several ingredients of the 
flesh thus gained and lost in the two cases may be tabulated as follows : 
Table 39. — Gain and loss of ingredients of flesh (body) of oysters during dialysis in 
11 floating 
Ingredients of flesh 
Percentages of in- 
gredients found by 
analysis. 
Gain (+) or loss (— ) dur- 
ing dialysis. 
Before 
dialysis. 
After 
dialysis. 
Expressed 
in difference 
of percent- 
ages, before 
and after 
dialysis. 
Expressed 
in percent- 
ages of the 
percentages 
in flesh before 
dialysis. 
James River: 
Water 
77. 99 
82. 77 
+4. 78 
+ 6.1 
Water-free substance 
! 22.01 
17.23 
—4.78 
—21.7 
Protein (N X 6,25) 
10.63 
8. 79 
-1. 84 
—17.3 
Fats (ether extract) 
2.61 
1.91 
—0.70 
-26.8 
Carbohydrates, etc 
6.56- 
4.98 
—1.58 
—24.1 
Ash 
2. 21 
1,55 
-0.66 
-29.9 
Potomac River: 
Water 
77. 90 
82. 06 
+4. 16 
+ 5.3 
Water-free substance 
22.10 
17. 94 
—4. 16 
-18.8 
Protein (N X 6.25)’ 
10. 31 
9. 09 
—1.22 
—11.8 
Fats (ether extract) 
2. 33 
1. 93 
— 0. 40 
'i— 17. 8 
Carbohydrates, etc 
7. 29 
5. 34 
—1. 95 
— 26. 8 
Ash. 
2.17 
2.58 
— 0. 59 
— 27. 2 
The gain of water as expressed in the excess of the percentage in 
the floated over that of the not-floated specimen is 4.78 (which is, of 
course, the same as the loss of water-free substance). This 4,78 is 6.1 
percent, of the 77.79 per cent, of water in the not-floated specimen. 
In other words, the percentage of water was increased in the process of 
osmose by 6.1 per cent, of its amount before the osmose. The corre- 
