CHEMICAL CHANGES OCCURRING IN OYSTERS. 21 



per cent; amino nitrogen, 59.1 per cent; ash, 52.3 per cent. Thus in 

 this experiment the actual loss of total solids is only 5.3 per cent of 

 the original amount present, probably soluble amino compounds and 

 inorganic salts, while the actual loss of amino acids is 19.2 per cent 

 and that of ash-forming substances is even greater, amounting to 26 

 per cent. As the osmotic loss is in each case 21.7 per cent, it is 

 clear that the actual loss of total solids is relatively slight compared 

 to it, while the actual loss of amino acids and other soluble constitu- 

 ents is as great as, or greater than, the osmotic loss. These figures 

 do not represent commercial practice, however, for, in general, oysters 

 are washed for about 30 minutes. 



Experiment 4- — I n this experiment the increase in volume and, 

 therefore, the osmotic loss are zero. The actual loss of amino acids 

 is also zero, and that of total solids is only 5.6 per cent. The actual 

 loss of ash is rather high but is far lower than when the washing is 

 done by the other method. 



Experiment 5. — The results of this experiment show a gain in 

 volume of 25 per cent. This makes the percentage figure for each 

 substance 80 per cent and the osmotic loss 20 per cent. As the 

 derivation of these figures already has been given in detail (Table 

 7), it will not be enumerated for this and the following experiments. 



Experiment 7. — The maximum osmosis was observed at the end of 

 30 minutes of washing in this method. The maximum osmptic 

 increase was 22.1 per cent, about 5 per cent less than that observed 

 in the case of air agitation. As will be shown later, this lower 

 value is due solely to the excessive handling inherent in this method 

 of repeated measurement and not to any difference in the methods 

 of agitation. The percentage of losses will be seen to correspond 

 rather closely to those observed in the air-agitation experiments. 

 It is interesting to note, however, that at the end of 40 minutes the 

 loss of total solids stopped, probably because of shrinkage in volume 

 caused by the excessive handling already mentioned. The per- 

 centage of amino acids, however, continued to fall. The ash was 

 apparently reduced to a minimum, the remainder being practically 

 all insoluble. The percentages in Table 7 are calculated from the 

 results at the end of 30 minutes, so that they closely represent com- 

 mercial practice. 



Experiment 8. — In the calculated results of this experiment the 

 30-minute results are used, as these are representative of commercial 

 practice. It will be observed that these results agree very closely 

 with those obtained in Experiment 7, except in the case of ash. This 

 difference is probably explained by the fact that the stock -came from 

 widely scattered beds, and the inorganic constituents were probably 

 dissimilar. 



