16 VOELCKER on the Chemistry of Food. 



pungent the longer it is kept between the teeth. On grinding, 

 moreover, it gives a bright yellow powder, altogether different in 

 appearance from powdered rape-cake. By these characters, and 

 especially by the pungent smell which mustard-cake developes 

 when mixed with cold water, mustard-cake is readily distinguished 

 from rape-cake. 



Neither mustard, nor rape-cake containing much mustard-seed, 

 should ever be used for feeding-purposes, inasmuch as the pun- 

 gent oil of mustard, which is gradually generated in the stomach 

 of the beast fed upon such cakes, acts as an irritating poison, 

 which may cause serious injury, and even death. 



Not long ago a case of poisoning with mustard-cake was 

 brought under my notice. A gentleman residing at Bibury, a 

 village eight miles from Cirencester, Gloucestershire, lost three 

 valuable beasts, which had been supplied with a small quantity 

 of oil-cake, a portion of which was forwarded to me for examina- 

 tion. The day before the cake was given to them they were per- 

 fectly well ; and after having eaten some cake, they became 

 suddenly so ill that two died before the veterinary surgeon could 

 administer an efficient remedy. The examination showed that 

 the cake which caused this mischief was either altogether a 

 mustard-cake, or contained a very large proportion of mustard- 

 seed. There remained thus no doubt that the beasts died from 

 the effects of the pungent oil of mustard. 



As the formation of the essential oil of mustard is prevented 

 by boiling water, and rape-cake often contains mustard-seed in a 

 degree which cannot but exercise an injurious effect upon the 

 health of animals, I would recommend to mix all rape-cake with 

 boiling water before it is given to cattle. By this simple means 

 any injury which rape-cake containing mustard-seed would pro- 

 duce, when not submitted to the action of boiling water, may be 

 entirely prevented ; but unless the water is in a state of perfect 

 ebullition, it will fail to accomplish this desirable end. 



In conclusion of these remarks on oil-cakes, I suggest to pur- 

 chasers of cake to submit it to the following easy tests : 



1. Examine a bit of the cake as to its taste and smell ; observe 

 that it is fresh, and free from any mouldiness. 



2. Examine another piece with a common pocket lens. This 

 examination will show whether the cake is a linseed or rape- 

 cake, inasmuch as the form of linseed and rape-seed are widely 

 different. Much more difficult is it to distinguish by the lens 

 mustard from rape cake. 



3. Mix in a tumbler about 1 oz. of the cake, broken into small 

 pieces, with 6 oz. of cold water. Good linseed- cake will form, 

 under these circumstances, a stiff, agreeably-tasting jelly, without 



