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



finely-ground oyster meats, weighed to within 0.1 gram. Tenth 

 normal solutions of acid and alkali were used. 



4. Total solids. — Place a thin layer of dried shredded asbestos on 

 the bottom of a thin lead dish, add a short glass rod, and weigh the 

 whole. Add about 5 grams of the ground sample, and weigh as 

 quickly as possible. Evaporate to dryness on the steam bath, and 

 dry for exactly 4 hours in a water-jacketed oven at the temperature 

 of boiling water. Weigh, and calculate the percentage of total 

 solids. During evaporation, the meat is stirred occasionally with 

 the glass rod. This stirring with the asbestos prevents the formation 

 of a crust which would hinder evaporation. 



5. Moisture. — Determined by difference from the total solids 

 results. 



6. Ash. — Weigh about 5 grams of the finely-ground sample as 

 quickly as possible into a previously ignited and weighed platinum 

 dish or crucible, drive off moisture at a moderate heat, and ignite at 

 the dullest red heat until the ash is gray in color. Extraction with 

 water, followed by a second evaporation and ignition, may be neces- 

 sary to secure a clean gray ash. Weigh, and report as percentage of 

 original sample. 



7. Salinity. 1 — Extract the ash obtained in the preceding deter- 

 mination with hot water, cool, and titrate against silver nitrate 

 solution containing 29.0575 grams of silver nitrate per liter of solu- 

 tion at room temperature. As indicator, use one or two drops of a 

 10 per cent solution of potassium chromate. One cc of this silver 

 nitrate solution is equivalent to 10 mg of sodium chlorid. Calculate 

 all chlorin as sodium chlorid, and report as percentage present in 

 original sample. 



SERIES I. 



In this series, determinations for amino-acid nitrogen and ammo- 

 niacal nitrogen only were run. A summary of results is given in 

 Table 1. 



The column headed "Shucker" represents oysters as taken from 

 the shuckers' dippers; "Riffle," oysters taken from the chute below 

 the riffle-boards ; "Commercial package," oysters after washing 

 and chilling, packed into cans ready to go into the refrigerator; 

 ''Refrigerator," oysters from the same day's run as those upon the 

 same line in the preceding columns, but sampled from the cans 

 remaining in the refrigerator one or two days later. 



1 These results are not exactly accurate, due to the fact that all the chlorin is not in the form of sodium 

 chlorid. As no analysis for oyster ash could be found in the literature, and there was no time to make such 

 analyses, the plan of calculating all the chlorin as sodium chlorid and reporting it as salinity was adopted. 

 Since all the data have been prepared on this basis, the results are comparable, and the error probably is 

 negligible, as the amount present is small in any case, and it is certain that a large proportion of the chlorin 

 is present in the form of sodium chlorid. 



