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



It had been assumed previously that the composition of oysters in 

 the shell would be identical with that of oysters taken from the 

 smickers' dippers. Table 4 shows that this is not the case, that 

 there is a slight but well-defined difference in composition. The 

 percentage of total solids and other constituents except water is 

 greater in the samples from the shuckers than in the sample of the 

 same stock shucked in the laboratory immediately before analysis, 

 while the percentage of water is correspondingly less. This difference 

 probably is due to the fact that the oysters drain for half an hour or 

 more while in the shuckers' dippers, and tend to lose a certain amount 

 of their body fluids, shell liquor, and adhering mucus. The shell 

 stock, being opened in the laboratory, had had less time in which to 

 lose water, and, therefore, was always poorer in solids. This marked 

 difference in composition between oysters which it would seem at 

 first glance should be of identical composition, shows very plainly 

 that the stock for each determination must be handled in exactly the 

 same way every day if the results are to be comparable. 



Table 4 is of great interest in showing the composition of oysters 

 during the various stages of progress through the oysterhouse, and 

 it shows also in a very striking manner the difference between the 

 old and the new methods of washing oysters, to the discredit of the 

 new methods, if amount of total nutrients is a proper criterion. 

 With the purpose of plainly showing this difference, the table has been 

 arranged in two parts, the analyses of oysters washed by the modern 

 method of air agitation in tanks and the analyses of stock washed by 

 the old method upon a perforated skimmer. 



Of the substances determined, amino-acid nitrogen and total solids 

 are taken for comparative purposes, as they are the most consistent 

 determinations made and most clearly represent the condition of the 

 oysters examined. The amino-acid nitrogen represents a truly 

 soluble constituent which would be dissolved out of the oysters by 

 the wash water. The total solids, though including most or all of the 

 amino-acid nitrogen, are in the main insoluble substances whose 

 apparent diminution in quantity is due largely to the distention of the 

 bodies of the oysters because of osmosis and loss of particles of solid 

 meat in handling or washing. A glance at the average values of 

 amino-acid nitrogen and total solids for the two classes of washing 

 shows that the content of both is much higher in oysters washed by 

 the old method than in those washed by the modern one. A brief 

 analysis of the results will show exactly how the two sets of figures 

 compare. Taking the amount of each of these substances present in 

 the shell stock as a basis upon which to calculate the losses, this 

 figure may be called 100 per cent. Thus, the amounts of each of the 

 constituents are expressed in percentages of the amount present in 

 the same stock while in the shell. For the shucked stock and the 

 commercial package, then, the figures in Table 5 are obtained. 



