158 



BULLETIN OF THE BUREAU OF FISHERIES. 



It is seen from Table 5 that the greatest glycogen formation from dextrose occurred 

 in experiment No. 44. Over 60 per cent increase occurred in 24 hours. Sea water from 

 the harbor where the oysters had been kept previous to the experiment was used, so 

 that during the sugar feeding (0.25 per cent dextrose in the water) the oysters experienced 

 no considerable change in the density of the medium. With lower densities some 

 glycogen formation appeared to occur in experiments Nos. 40, 41, and 42; but the results 

 of experimets Nos. 40 and 41 when compared with the control, experiment No. 45, are 

 not significant increments. This series of experiments (Nos. 39 to 45) was done early in 

 September when glycogen formation in oysters is at its height under natural conditions, 

 so that the oysters kept in a small amount of aerated but unchanged sugar-free sea water 

 were able to show a significant increase in glycogen during 24 hours. Water of specific 

 gravity of 1.015 to 1.016 does not so completely inhibit glycogen formation in oysters 

 that have previously been in water of specific gravity of 1.022 to 1.023. Examination 

 of the results of experiments reported in Table 2 yields additional evidence on this 

 point. An increase in the specific gravity of the sugar-containing medium may also, 

 within certain limits, allow considerable glycogen formation. This is shown by a com- 

 parison of the results of experiments Nos. 29, 30, 31, and 35 as reported in Table 3. 



An attempt to study the effect of the varying concentrations of specific inorganic 

 salts was made. The immediate object was to find the effect on glycogen storage of 

 adding phosphates to sugar-containing water whose density was low enough to check 

 the glycogen process. The experiments as reported in Table 6 show a tendency of 

 phosphates to interfere with glycogen storage. The experiments, Nos. 61, 62, and 63, 

 in which phosphates were added, all resulted in a lowered glycogen content of the oysters 

 although sugar was plentifully furnished. 



Table 6. — The Effect of Phosph.'vtes on Glycogen Formation from Sugar in Diluted SEa 



Water. 



Experi- 

 ment 

 No. 



Treatment of oysters (15 used for each analysis). 



Ash in 

 dried 

 meats. 



Glycogen 



in 



dried 



meats. 



Glycogen 

 in ash- 

 free 

 solids. 



In experiments Nos. 61 to 65 a mixture of equal parts of sea and fresh water (sp. gr. 

 i.oio) was used. 



Control analysis to be compared with Nos. 61 to 65 



In aerated, diluted sea water, with 0.15 per cent disodium phosphate and 0.25 per cent 

 dextrose, 24 hours 



In aerated, diluted sea water, with 0.5 per cent disodium phosphate and 0.35 per cent 

 dextrose, 24 hours 



In aerated, diluted sea water, with 0.5 per cent disodium phosphate, 0.35 per cent dex- 

 trose, and 0.25 per cent calcium chloride, 24 hours 



In aerated, diluted sea water, with 0.25 per cent dextrose, 24 hours 



In aerated, diluted sea water, without addition of salt or sugar, 24 hours, as a control to 

 Nos. 61, 62, 63, and 64 



Per cent. 

 29.27 



21.37 



24.07 



19-77 



21, 31 



Per cent. 

 10. S3 



9.2s 



7-32 



10. 76 

 12.50 



10.67 



Per cent. 

 14.90 



11.77 

 9.65 



13.40 

 15. 88 



The possibility of the formation of glycogen from dextrose by oyster meats sepa- 

 rated from the shells was tested, because in the present-day practice of the oyster indus- 

 try the meats, before packed for shipment, are washed freely with tap water during 

 periods varying in different estabHshments from a few minutes to several hours. If the 

 glycogen increment, then, could be obtained during this process by addition of glucose 

 to the wash water, an obvious economy would be attained. Only one such experiment 

 is reported, as time and opportunity for conducting others have not yet been found. The 

 result of this, shown in Table 7, was entirely negative. This might be expected physio- 

 logically. With the circulation destroyed, death coming on in the tissues, and metab- 



