AND THE SUBSTITUTES FOR OIL-CAKES. 65 



examination of oil-cakes, the woody fibre was determined sepa- 

 rately by me, and gave 14 per cent, as the average amount of 

 woody fibre in good oil-cake. The other constituents which are 

 particularly valuable in oil-cake namely, ready-formed oil or 

 fat and ready-formed flesh are very abundant : more so than in 

 almost any other description of food. The proportion of oil in 

 good linseed-cake amounts to from 10 to 12 per cent. ; and the 

 proportion of flesh-forming constituents amounts to from 24 to 

 27 per cent. Oil-cake, therefore, possesses high fattening pro- 

 perties, and at the same time it is well adapted for supplying the 

 muscle of growing stock ; and there is hardly any description of 

 food which, within the same bulk, contains so much nutritive 

 matter ; for if you compare the composition of oil-cake with the 

 composition of some other articles of consumption which are 

 held in high esteem by the farmer, you will find that none can 

 stand comparison with oil-cake. If you take, for instance, the 

 composition of barley, you will find that it is rich indeed in fat- 

 producing matter in starch, which is readily converted into fat, 

 but is, comparatively speaking, poor in flesh-forming consti- 

 tuents. Barley-meal, for this reason, is usually given to fattening 

 animals, but it is not given with so much advantage as oil- 

 cakes to young stock or milch cows. In short, oil-cake is a more 

 concentrated food, and perhaps for some particular purposes it is 

 too concentrated to be given with advantage or with profit to 

 animals. It is a nice question to decide in what proportion oil- 

 cake shall be given to animals, and is one which is often referred 

 to the chemist. It is frequently asked, in what quantity will oil- 

 cake pay the best? But questions of a practical character can 

 not be well decided by theoretical reasoning ; they can only be 

 decided by experiments in the feeding-stall, and who is in a 

 better position to make these experiments than the practical 

 farmer ? The chemist exercises judgment, and therefore cannot 

 readily be found to give an opinion on such a purely practical 

 question. It is a question which has a great deal to do with 

 s. d., and it is for the farmer to decide what is profitable for 

 him, and not for the chemist to prescribe to the farmer what is 

 the best for his profit. It must be the aim of the chemist to 

 give a lucid exposition of the leading principles of the science 

 which he professes to the practical farmer, and to leave them to 

 him, and if he is an intelligent and sensible man, and advancing 

 with the times, he will apply them to practical purposes. How- 

 ever, chemistry may frequently give useful hints to the practical 

 farmer, and the case of oil-cake affords him an opportunity of 

 bringing them out. We know practically that the nutritive 

 value of different samples of oil-cake varies very considerably, 

 and the question naturally arises What is the cause of this 



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