155 



necessary. A more extensive use of such a preservative 

 might also be taken into consideration if there should be 

 further confirmation of the supposition that the taste of this 

 rice is improved by keeping it for 2 or 3 months. 



For the purpose of finding a preservative for unpolished 

 rice which was in every respect suitable, storage proofs 

 were taken and continned as long as possible with chemicals 

 which came principally into consideration, such as oxide 

 of calcium (CaO), formaline, sulphurous acid (S0 2 ), alcohol, 

 chloroform and carbontetrachloride (CC1 4 ). Proofs with ether 

 were given up, because of its great volatility and combustibility 

 and because of its forming explosive mixtures with the air; it 

 could not therefore find practical application on a large scale. 



The influence of the first named preservatives was now 

 traced, to find out in how far, especially in case of long 

 storage, they affected the smell, the taste, the breakage 

 and the brittleness, besides the amount of damage done 

 by insects, and also what was their effect with regard to 

 the prophylactic value. A special chapter of this treatise is 

 devoted to this latter point, as this is of the most importance. 



Generally speaking, the following particulars as to the 

 results of these experiments were remarked. 



There was no question of the appearance of insects under 

 the influence of any of the preservatives mentioned, except 

 in the case of CaO, which seemed rather to encourage than 

 to prevent the damage done by weevils. 



An essential difference between the grains of rice which 

 still retained the silver-skin and the grains of polished kinds 

 of rice was found as to the breakage. The formation 

 namely of continuous transverse cracks, which appeared 

 when some of the preservatives were used, was prevented 

 by the presence of the silver-skin. Polished rice which had 

 been preserved for months with alcohol and CaO showed 

 more than 50°/ o cracked grains, while unpolished rice of the 

 same kind did not show a single burst after being preserved 

 under exactly similar conditions. 



