CHAP. XII. 



ADULTERATED LINSEED CAKES. 



203 



TABLE II. 



" In the figures of these there is nothing absolutely exceptional. In 

 the mill- sweepings mixture, alone, is the sand sufficiently high to call 

 for comment. Unlike in the admixture of rape, the present series are 

 very discernible by chemical tests for the presence of starchy bodies. 

 The cake with mill-sweepings in it had a somewhat dirty appearance, 

 and the presence of cockle, buckwheat, and mill-sweepings was dis- 

 cernible clearly by the microscope. From what I have stated, it is 

 clear that it is quite fallacious to decide by the figures of chemical 

 analysis alone whether a cake is pure or not, and that to determine 

 this point a careful microscopical examination, made by an experienced 

 observer, is necessary. It would be quite hopeless to give any direc- 

 tions to non-experts by which adulteration could be detected. 



" What should then be termed a ' pure ' cake ? Absolute purity, 

 i.e., that the cake should not contain a particle of anything not linseed, 

 is an impossibility. As absurd would it be to say that the presence of 

 a single bit of wheat-husk or straw in a sample of wheat-flour rendered 

 the latter an adulterated article. Much is heard of the term ' 95 per 

 cent, pure ' as applied to linseed-cakes, but whilst it is quite possible 

 to determine by mechanical separation the exact percentage of linseed 

 in a sample of seed, yet, after the materials have been crushed and the 

 oil expressed, no means exist, chemical or otherwise, of separating and 

 ascertaining absolutely how much of a cake consists of linseed only. 

 The most that can be given is an approximation. 



" The evil of accepting a standard of 95 per cent, is that, in so doing, 

 no cognisance would be taken of what the nature of the other 5 per 

 cent. was. For instance, some impurities, such as castor oil bean, 

 might be contained in it,\of which a far smaller amount than the 

 allowed 5 per cent, would render the cake positively poisonous. To 



