RAPE-CAKE ITS ADULTERATIONS. 365 



terating substances that can be used with linseed, does 

 not exist here, and other oleaginous seeds may be readily 

 mixed with it, without appreciable injury to the quality 

 of the oil. On the other hand, the low price of the 

 oil and of the cake prevents the use of any but the 

 cheapest materials for the purpose. The chief adulterat- 

 ing substance appears to be mustard, or rather, perhaps, 

 the "dross," as it is termed, obtained in grinding it for 

 table use. This not only acts as an adulterating substance, 

 by lowering the proportion of feeding compounds in the 

 cake, but it adds to it injurious properties, which render 

 it quite unfit for such purposes, and thus, in another way, 

 depreciates its value. 



These points, which in more than one instance of late 

 have led to fatal results, 1 we have to discuss hereafter 

 (page 400) in the chemistry of the mustard crop. 



Dr. Anderson gives us the following physical characteris- 

 tics of the genuine cake, to assist us in our selection of 

 samples in the market: Rape-cake of good, quality, he 

 says, is distinguished by its greenish colour, and by its 

 more mottled appearance. When broken, the yellowish 

 pieces of the inside of the seed and the dark fragments of 

 the outer coat may often be very distinctly seen. When 

 mixed with water, in the proportion of 100 grains to the 

 ounce, it forms a semi-fluid paste, which runs like a thick 

 fluid. The general colour is pale, studded with the dark- 

 coloured particles of the outer husk. Its smell is oleagi- 

 nous. Caustic potash gives a strong green colour. These 

 qualities vary considerably in different samples, and 



1 From the evidence adduced at the trials (see Agric. Gaz., 1855, pp. 42 and 

 73, and 1859, p. 730) it would appear that, in both cases, the cake was made 

 from mustard and not from rape seed. A large quantity of seed is annually 

 imported for oil purposes, under the name of East Indian or Guzerat Rape, 

 which actually is the produce of plants belonging to the genus " Sinapis,' and 

 not to the rape family (Brassica) at all. Hence the fatal effeets produced by 

 employing its residuum or cake for feeding purposes. 



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