644 



The fresh or dry residue contained no acid to speak of, but in the 

 fermented residue nearly 20 per cent of tlie whole dry substance con- 

 sisted of acids of doubtful nutritive value. 



As regards the protein comjiounds, the same principles apply. By 

 fermentation these are converted in i)artinto amide-like compounds, and 

 as such, possess a certain nutritive value, though decidedly less than 

 the albuminoids from which they are formed. Thus Julius Kiihn esti- 

 mates the effect of the amides in economizing protein {ah eiiceiss- 

 sparenfJe Niihrstoffe) as equivalent only to carbohydrates. 



In the fresh or dry diffusion residue practically none of the nitrogen 

 was in the amide form, but in the fermented material on the average 8.8 

 per cent of the nitrogen was in this form and the amount in individual 

 cases was much more, even as liigli as 24.3 per cent. 



The facts at hand imply that the more soluble and easily digestible 

 albuminoids are the first ones to be decomixised by fermentation, and that 

 a not inconsiderable ])ortion may be com|)letely decomposed. It there- 

 fore seems probable that the residual protein would be less digestible 

 than the whole protein in its original form. " 8o far as the digestibility 

 of tlu! [irotein of diffusion residue is concerned, the effects of fermenta- 

 tion have not been accurately tested previous to these investigations, 

 but for all other feeiling stuff's which have been subjected to the process 

 {KiuHriuerumi) it has been juoved that a decided diminution of digest- 

 ibility of the protein takes place. Such is the outi'ome of the investi 

 gations from those of Gustav Kiihn n'garding the feiinentation of bran 

 to those of F. Albert regarding the so-called green-jtress fodder." As 

 is shown by the feeding experiments made in connection with the inves- 

 tigati(tns here described, the digestibility of the i)rotein of diffusion 

 residue is materially diminished by fermentation when stored. The 

 following figures re]>resent averag*' results of testes by Stutzer's methotl : 

 Coefficients of digestibility of i)rotein in dried diffusion residue 86,7 

 per <ent, in fermented diffusion residue 7.{ per cent. That the diges- 

 tibility of the protein was not essentially diminished in drying by the 

 process used, was abun<lantly proved. 



[While the general facts are as stated there are exceptions, as 

 appears in some of the details of the investigations here cited.* Thus 

 in certain fee«ling stuffs which contain but little jirotein, and that in 

 less digestible forms, it appears that the digestibility of the protein may 

 be favored by fei-mentation. In how far this is due to changes in the 

 l)rotein compounds themselves and in how far to alterations in the 

 chemical or mechanical characters of the other compounds or the tis- 

 sues of the feeding stuff's, is by no means c<M'tain, Xot only the work of 

 the chemist, but also that of the bacteriologist and the vegetal)le histolo- 

 gist will be needed to clear up this interesting and important question.] 



* See likewise the results of observatious reported l>_v Morjuu, Jour. f. Lautlw., H6 

 (1H88\ p, .318, and by Kellu.-r, Kozai. and M<iri. Laiidw. Vers, Stat., 39 (1891), p. 113, 

 aad Experiuieut Station Kecord, vol. in, p. 266, 



