416 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



weed seeds and impurities found therein, in amounts varying 

 from 1-| to 70 per cent. Some twenty-three different kinds 

 of seeds were found, besides various sorts of clover and grass 

 seeds. Among these were seeds of rape, red or wild mus- 

 tard, white mustard, dodder, purging-flax, corn-cockle, millet, 

 sheep sorrel, dandelion, knot-grass, buckwheat, etc. Of these, 

 rape-seed is itself quite valuable for cakes, and a number of 

 the other seeds are of themselves harmless. Of the materials 

 used in the manufacture of mixed or compound feeding-cakes, 

 a list of more than thirty kinds is given, including rape cake, 

 groundnut cake (peanut), cotton cake, palm-nut cake, castor- 

 oil cake, curcas cake, olive cake, rice meal, bran, and sawdust. 

 " Some of the materials which, like curcas beans or castor-oil 

 cake, are downright poison, do not frequently occur, and 

 generally get mixed with feeding-cakes through ignorance or 

 carelessness ; as when the sweepings of warehouses, grana- 

 ries, or provision stores are pressed into compound cakes." 

 Besides curcas and castor-oil beans, no other positively poi- 

 sonous ingredients were found in linseed cakes. In rape-seed 

 cake, however, black or wild mustard frequently occurs in 

 such quantities as to render it entirely unfit for feeding pur- 

 poses. 



The injurious effects observed from the feeding of oil-cakes 

 are often due, not to any poisonous adulteration, but rather 

 to a mouldy, rancid, or heated condition of the cake. The 

 evil effects of mould and rancidity are discussed at some 

 length in Professor Voelcker's report. Instances are cited of 

 death of animals from eating mouldy oats as well as mouldy 

 feeding- cakes. A number of analyses are given of pure, 

 adulterated, and poisonous feeding-cakes, which show that 

 the mere chemical analysis of a cake does not necessarily 

 throw much light upon it as a feeding-cake. A much surer 

 method of detecting adulterations is found in microscopical 

 examination. The differences in structure of the cuticle and 

 other parts of the different kinds of seeds used in the manu- 

 facture of oil-cake are quite characteristic when examined by 

 the microscope, as is illustrated by diagrams in the report. 

 In general, Dr. Voelcker finds in these examinations great rea- 

 son for carefulness in the purchase of oil-cake for stock. As 

 regards the relative value of American and English linseed 

 cake, Dr. Voelcker says that," as a rule, the bulk of American 



