PRESERVATION BY DRYING. 239 



It is well to remember that drying and smoking do not kill the animal 

 parasites that may be in the meat, like trichina or tape-worms. 



Fruit. The drying of apples, squashes, pumpkins, and other 

 vegetables is a common process of farm life. In warmer regions of 

 the earth the sun's rays are sufficient to dry many fruits for preserva- 

 tion. Raisins and figs are thus prepared. In colder regions arti- 

 ficial heat must be employed. By the use of artificial heat it has 

 been found possible to preserve, by drying, a large number of fruits. 

 Pears, prunes, plums, raspberries, blackberries, blueberries, and straw- 

 berries represent some of the farm products which readily yield to 

 this method of treatment. In fruit prepared in this way the water 

 is not all removed, sometimes as much as 30 per cent, being left. 

 In most cases there is considerable sugar in the dried product which 

 aids in the preservation. In pears there is some 30 per cent, of 

 sugar, while in raisins there is about 60 per cent. It must always 

 be remembered that drying does not destroy the bacteria, but only 

 checks their growth, and if the fruit has been exposed to a possible 

 contamination of pathogenic bacteria, the drying does not remove 

 the danger. This method of preserving fruits naturally affects their 

 flavor and is frequently quite unsatisfactory for this reason, although 

 it does not materially affect their nutritive value. In recent years 

 hydraulic pressure has been used to extract the water with results, 

 on the whole, superior to the extraction by simple drying. 



Hay. One of the most important applications of the drying 

 process is in the preparation of hay. The fresh grass contains 

 so much moisture that it could not be preserved in masses without 

 undergoing extensive decomposition, and to obviate this the farmer 

 resorts to the simple plan of drying out some of the water. But 

 this phenomenon of drying is not always as simple as it looks, and 

 sometimes a fermentation is certainly involved. Where the climate 

 is moderately dry and the sun hot, the simple method of exposing 

 the grass to the sun for a few hours is. most widely adopted. But 

 such a method is not possible in regions where there is likely to 

 be a great deal of rain. 



Curing of Hay by Self -fermentation. In countries where rains 

 are frequent and sunshine rare, the sun's rays cannot be depended 



