THE FARMER'S MAGAZINE. 



31 



average composition of linseed oil-cake shows that 

 it contains 1279 per cent, of oil; 27"2S percent, 

 of flesh-forming prmciples; 4r36 per cent, of 

 heat-producing constituents; 6"13 per cent, of ash 

 (phosphates); and 12'44 per cent, of moisture. 

 Good linseed cakes contain, therefore, ahout the 

 same amount of llesh-forming principles as heans 

 and peas; but in the production of fat, linseed 

 cakes are superior to beans, peas, Indian corn, 

 or any of the other kinds of food. 



Rape Cakes. — Until lately, rape cake, or rape 

 dust, was chiefly used as a manure. It has, how- 

 ever, been ascertained that, although not generally 

 relished by cattle on account of its tendency 

 to rancidity, it is liked by sheep. If rape cake is 

 mixed with 5oi7i«^ water for some time before being 

 used, it may be given safely either to cattle or 

 sheep, and the former will relish it better than 

 in its natural state. Rape cake contains 10.68 per 

 cent, of moisture; 11.10 per cent, of oil; 29.53 

 per cent, of flesh-forming constituents ; 40.90 per 

 cent, of heat-producing elements ; and 7.79 per 

 cent, of ash, or bone materials. An examination 

 of the relative proportions of these constituents 

 will show the value of rape cake as a feeding 

 material, the greatest drawback against its use 

 being the readiness with which the oil contained in 

 it becomes rancid, thereby rendering it less palata- 

 ble to stock. Rape cake is often adulterated with 

 mustard cake, to which it bears a resemblance; 

 and this adulteration renders it not only of less 

 value, but positively dangerous to those animals 

 that may eat it. Cases have often occurred of 

 mustard cake being substituted for rape cake, and 

 death ensuing from the use of it. The following 

 tests, given by Dr. Voelcker, will be found of great 

 value to the purchasers of oil cakes :— 



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 a rape-cake, inasmuch as 

 the forms of the linseed and rape seed are widely 

 different. Much more difliicult is it to distinguish 

 by the lens mustard from rape-cake. 



3. Mix in a tumbler about one ounce of the 

 cake broken into small pieces, with six ounces of 

 cold water. Good linseed-cake will form imder 

 these circumstances a stiflf agreeably-tasting jelly, 

 without separating any water. Rape-cake will 

 become less gelatinous, and separate a yellowish or 

 brown rather bitter tasting hquid. Mustard-cake, 

 likewise, will become a little gelatinous, and sepa- 

 rate a brown liquid which, possesses the character- 

 istic taste and smell of essential oil of mustard. 



Rape-cake, fraudulently or naturally mixed with 

 mustard-seed, under these circumstances will ex- 

 hibit a similar behaviour to that of mustard cake, 

 and by the degree of pungency of taste and 

 smell, when compared with pure mustard-cake, 

 will afford the means of estimating approxi- 

 mately the amount of mustard which the cake 

 contains. 



We have now arrived at an important and 

 interesting branch of our subject, namely, the 

 amount of nutrition contained in the different 

 varieties of grasses. Until recently, our knowledge 

 of the nutritive qualities of the grasses was imper- 

 fect, and based chiefly on speculative opinions 

 rather than ascertained facts. But we have now to 

 thank Professors Way, Anderson, and Voelcker 

 for having investigated the subject, at least to 

 a certain extent; and although there still remains 

 in this respect a wide field for the exercise of " the 

 detective functions " of analytical chemistry, still 

 we have clearer data to guide us, in the results of 

 the analyses conducted by the eminent men we 

 have named. 



There are many causes which influence the 

 nutritive value of hay, and even of the grasses in a 

 fresh state. The period at which the grasses are 

 cut, Vv'hether before flowering, when in flower, or 

 when dead ripe, influences the nutritive qualities to 

 a very considerable extent. Thus, of two samples 

 of red clover, one of which was cut when begin- 

 ning to flower, and the second in fourteen days 

 after, when in full flower, the latter contained 

 nearly 10 per cent, less of nutritive substances and 

 11 per cent, more indigestible woody fibre than the 

 former. This proves to us that the longer that 

 clover is allowed to remain uncut, after it is in 

 flower, its nutritive properties become rapidly dete- 

 riorated, the starch and other elements of respiration 

 and fat becoming changed into woody fibre. Again, 

 exposure to continued rain lessens the nutritive 

 value of hay, inasmuch as the juices are thereby 

 washed out, and it is only the insoluble constituents 

 which remain. Heating or fermentation also acts 

 injuriously, because by means of it the nitrogenised 

 part, or the flesh-forming constituents, are not only 

 rendered less, soluble, but, if the fermentation 

 is allowed to proceed to a considerable extent, 

 these become destroyed — are changed, in fact, into 

 other compounds, amongst which are vinegar and 

 ammonia. Grasses also, when grown on dift'erent 

 descriptions of soils, will often present very oppo- 

 site results, when their nutritive qualities are tested 

 by analysis. Thus the analyses of dry clovers 

 grown in Scotland, made by Dr. Anderson, showed 

 an average amount of flesh-forming substances to 

 be 14.40 per cent. ; whilst Drs. Voelcker and Way, 

 on clovers grown in England, showed an average 



