THE OYSTER AND THE DOCTOR. 329 



told you that after being rendered soluble by conversion into 







dextrin and maltose, it was absorbed and carried to the 

 liver by the portal veins, when it was reconverted into an 

 insoluble animal starch called glycogen. The soft fawn- 

 coloured mass which forms the bulk of the oyster is its 

 liver, which is almost entirely composed of glycogen, but 

 kept from actual contact with it during life, is its appro- 

 priate digestive ferment the hepatic diastase. When the 

 oyster is crushed by mastication, the glycogen and diastase 

 are brought in contact, and digestion takes place immedi- 

 ately, without any aid from the gastric secretions of the 

 eater. In cooking the oyster, this hepatic diastase, like 

 all digestive ferments, is destroyed by heat, and digestion 

 of the bivalve must take place in the ordinary way." (h] 



In connection with the above I append a Guide to 

 Digestion. I have extended the list as far as is known, 

 and based its accuracy on that of the highest authorities in 

 the medical profession. Strictly speaking, I need only 

 have confined myself to the oyster alone ; but the remain- 

 ing edible members of the shell-fish genus appealed so 

 pathetically for equality of honour with the oyster in the 

 useful record of their digestive qualifications, that I could 

 not withstand the appeal. But, no sooner granted, the 

 Fishes likewise aspired to and sought the same honours. 

 " Is it not natural," they seemed to me in thought to 

 argue, " that the reader, knowing and having learned so 

 much about the oyster and his kin and kind, would also 

 wish to learn how we too serve man in the digestive regions 

 of his wonderful economy?" Could I gainsay this plau- 

 sible argument ? No ! Therefore have I given the list in 

 full, for the reader's information. 



(h) " Some of the principles governing the preparation of food for the 



sick." Dietetic Gazette. 



