THE STORY OP OUR FOODS 23 



different substances required, such proportions not 

 being offered by one food taken by itself. Thus, 

 white fish is largely deficient in fat, and with this 

 article of diet some form of fatty sauce is usually 

 taken ; whereas on the other hand, fish represented 

 by salmon, herring, and eels, containing a fair pro- 

 portion of fat eels especially containing much fat 

 do not require the addition in question. Salads 

 are made more nutritious by the addition of eggs 

 and oil ; and a rice pudding, deficient in fat, is made 

 a very much more nutritious article of diet by the 

 addition of eggs and milk. In the same way foods 

 which are apt to be somewhat tasteless are rendered 

 more savoury by certain additions being made to 

 them. Thus with fowl, salt food in the shape of 

 ham or bacon is taken ; and the familiar combination 

 of salt beef and greens is, in its way, to be com- 

 mended the greens containing potash and thus 

 tending somewhat to modify the salt of the beef. 

 The value of green vegetables, it may be stated, 

 does not consist in their affording much nourish- 

 ment, but in their supplying us with the minerals, 

 especially potash, which we have seen to be a 

 necessary constituent of the blood. Even when we 

 toast bread we cause it to undergo a change which 

 converts so much of its starchy contents into sugar. 

 We thereby assist the action of the saliva of the 

 mouth, the duty of which is to convert starch into 

 sugar as will be afterwards shown. Such habits in 

 the taking of food, as has been said, have originated 

 as the result more of experience than of scientific 

 wisdom, but science has at least supplied reasons 

 why such combinations are beneficial, and in this 

 respect has given a powerful sanction to the adop- 

 tion of rational modes of feeding. 



