70 THE NUTRITIVE VALUE OF DIFFERENT OIL-CAKES, 



otherwise useful food, comparatively speaking, useless. And I 

 believe that the difference we observe in the practical effect of 

 cotton-seed and poppy-cake, and even of rape-cake, is particularly 

 if not in a great measure due to the fact that the three last- 

 mentioned cakes contain a larger amount of indigestible fibre 

 than good linseed-cake. Thus you will find that there is always a 

 good reason for the experience which a practical man possesses 

 respecting the nutritive value of food or the fertilising properties 

 of manure ; and it remains for us to find out those reasons, and to 

 put the practical man in possession of them, so that he may 

 judge for himself in similar cases. Oil-cake of every kind, and 

 more especially linseed-cake, as mentioned in the beginning of 

 this Lecture, is a very concentrated kind of food, but, unfortu- 

 nately, its high price precludes its general application in many 

 instances, and it has been the desire of late to introduce substi- 

 tutes for cake as well as substitutes for barley-meal, which at 

 present is very high in price. 



Among those substitutes the following may be mentioned : 

 carob-beans, Indian corn, Irish moss, and rice-meal. 



COMPOSITION OF CAROB BEANS (KENSINGTON). 



in Natural State. Dry. 



Water 14-22 



Sugar 54-07 



Mucilage and other digestible respiratory principles 17'41 



Woody fibre 3'88 



Oil ^ -96 



Flesh-forming principles 7*72 



Soluble inorganic matters (soluble ash) 1-12 



Insoluble inorganic matters (insoluble ash) .. .. '62 



100-00 100-00 



First, with respect to the carob-bean, I would observe that 

 perhaps its value as a feeding material has been over-estimated, 

 and the price which is sometimes paid for it 127. per ton in 

 comparison with oil-cake, is far too high. Carob-bean is a food 

 which is exceedingly rich in sugar, but is, comparatively speak- 

 ing, poor in flesh-forming substances. For these reasons it is 

 well adapted for fattening purposes, but even for these purposes 

 it is not, I believe, so useful as oil-cake, for although we have a 

 large quantity of sugar in the carob-bean, the quantity of fat, or 

 oil, is small, and does not amount to one per cent., whilst in oil- 

 cake we find at least from 10 to 12 per cent, of ready-formed oil 

 and a considerable quantity of mucilage or gum, which fulfils the 

 same purpose to which sugar is applied in the animal economy. 

 Now the power of mucilage, sugar, or oil in producing fat in the 

 animal economy depends mainly on the proportion of carbon 

 contained in sugar, gum, mucilage, or fat. In sugar, gum, or 

 mucilage the proportion of carbon, in round numbers, amounts 



