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CHEMICAL DEPARTMENT. 



does not contain enough albuminoid matter to be genuine, and 

 No. 13 contains too much. We can tell that by referring to the 

 composition of linseed itself. 



The average samples of linseed supplied in the market con- 

 tain 20 per cent, of albuminoid matter and 36 per cent, of oil. 

 The composition of the seed fluctuates somewhat according to 

 the district it comes from, and according to the conditions of its 

 growth ; but if the linseed is pure, these fluctuations are not 

 very great. When oil is extracted from the seed the residual 

 cake is richer in albuminoid matter in proportion as the amount 

 of oil extracted is greater. Taking 20 per cent, of albuminoids 

 and 30 per cent, of oil as our basis, we can easily calculate how 

 much albuminoid matter a cake should contain when we know 

 how much oil is left in it. The following table expresses the 

 amount of albuminoid matter which corresponds to certain 

 percentages of oil in an average sample of commercially pure 

 linseed cake : — 



If we apply this test to the analyses given above, we find that 

 almost all the so-called linseed cakes are deficient in albuminoid 

 matter. It is evident, therefore, that they are either made from 

 impure linseed, or that some other substance has been added in 

 the process of manufacture. 



If the analyses given above may be accepted as representing 

 the average character of the linseed cakes in the market, it is 

 not so much the want of oil that denotes them as the want of 

 albuminoids. So far as my experience goes, there are very few 

 pure linseed cakes in the market, and microscopic examination 

 shows that this is not so much due to the crushing of impure 

 linseed as to the addition of other substances, chiefly locust bean 

 meal. The effect of adding locust bean meal to linseed cakes 

 is to diminish the proportion of albuminoids and oil, and to in- 

 crease the proportion of carbohydrates. The reduction of the 

 proportion of albuminoids diminishes the concentration of the 

 fodder, but it is not without its compensation, for the carbo- 

 hydrates added consist largely of sugar, which is easily digested, 



