. Composition and Nutritive Value of Straw. 23 



hay. Oat-straw, so harvested, ought therefore to be as useful in 

 repairing the waste of muscle of working oxen and horses as 

 common hay. It is indeed much relished by animals, especially 

 by working horses, who have good reasons for their predilec- 

 tion, one no doubt being the larger proportion of flesh-forming 

 matters that it contains, and another probably its more succulent 

 and palatable condition. 



2. The greater proportion of the albuminous or protein com- 

 pounds exists in the green straw in a condition in which they 

 are soluble in water, and therefore in all probability more easily 

 digested than they are in an insoluble state. 



3. Towards maturity the amount of albuminous and nitro- 

 genised compounds dwindles down to about one-half. Thus, 

 whilst green straw contains 8J- per cent, of nitrogenised matters, 

 that which is fairly ripe contains only 4 per cent. The soluble 

 and insoluble protein compounds likewise appear to diminish at 

 precisely the same rate. 



In green straw we have, in round numbers, 5J per cent, of 

 soluble nitrogenized matters against 2*6 per cent, in the fairly 

 ripe sample, and 3 per cent, of insoluble protein compounds 

 against 1J per cent. 



The question arises, what becomes of all the nitrogenised 

 matter, which disappears with extreme rapidity when our cereal 

 crops arrive at maturity? Although I have not made any special 

 experiments with a view of ascertaining this point, it does not 

 appear to me likely that this matter is all stored up in the grain ; 

 and I have not much doubt that, as observed by Messrs. Lawes 

 and Gilbert, a considerable loss of nitrogen takes place in the 

 growth of corn-crops, which loss is particularly noticeable when 

 the crop arrives at maturity. 



4. In over-ripe oat-straw a still further, though inconsiderable, 

 diminution of nitrogenised matters took place. But whereas, in 

 the two other samples, the soluble nitrogenised matter greatly 

 preponderates over the insoluble, the reverse is the case in the 

 over-ripe specimen. In this sample it will be seen that the 

 insoluble protein compounds amount to 2iV per cent, and the 

 soluble to only 1 jV per cent. 



Over-ripe straw then is not only absolutely poorer in albu- 

 minous or flesh-forming matters than fairly ripe samples, but it 

 likewise contains these important constituents in a less soluble, 

 and therefore less digestible, form. 



5. The proportions of oil in the three samples differ but little. 



6. Of sugar, gum, and other matters soluble in water, not less 

 than 16 per cent, occurs in the green straw, as against 3 per cent, 

 in the over-ripe straw. In the fairly ripe sample 10 J per cent. 



