SILACE.

Dominion, Volume 2, Issue 492, 27 April 1909, Page 10

SILACE.

WHY IT KEEPS. \ Dr. E. J. Russollj of tho Rothamsted Ex- I perimental Station, in a recent number of the! V'Journal of Agricultural Science," discusses tho keeping qualities of silage. As is' well known, when green parts of Jiving plants are cut/up and packed in a loosely-covered vessel, allowing entranco of air, mould soon t nmkes its appearanco, and decdmposition be- J gins. -The mass becomes alkaline, and is ulti-mat-oly converted into black humid bodies, J quit? unfit for cattlo food. But, when air ,is excluded, the result is radically different. I No mould develops, tho temperature rises,, the mass takes on a grefcnisfi-brown corlour ( and characteristic odour, bccomes acid, I and for a long period is suitable.for caWe I.

T food:;'; The. former, ho explains, is a putro- . factivo'changcj the ;■ Dr. evidently.;docs 1 : not favour the hypothesis that the : '"changcs'v areicaijsc'd,•.*•>& fermentations being'. brought about' liy ■micro^rgau^sras|v:aild■ ,,: e» : qlvilig^ , ; , so , .■7 l lJ!Ucl^hcht , .■ that everytliiiiii.is killed,.and .'the; mass,- consequently,; sterilised'.'' This theory,. he-states, "may be'dismissed at mire, since silage invariably contains bacteria, and is never - sterile..Bacteria must obviously. play .somo I part, oven if only a sccojidaryt.part'jill' the 1 process,V' '''Three' : sets'.-I'qf'^asbntsjv.'jh'o' considered, 3 enzymes (agents which'givc':risc': : to fenncnta--3 tion), and bacteria. I'utting together his ; results, l)r; Kussell sketched out fairly com- - pletely what'happened. AVlien the cells wero b put in' they were, alive, "and their vital functions continued. . Respiration wont, on, and f sugar, etc., was u.wd up ( . but in tJio absenco s of air oxidation was' not "complete; and vnri--5 ous acids and- other.' 1 chemical 'combinations - were formed. Tho heat developed" during , the chemical; action-raised the temperature t of tho mass, and respiration was accelerated. • But, as no more material was being clabor- ■ ated, aiid only decomposition was 1 taking r placo, the process soon came to an end. ,Tho ' colls then died for more substance to break ■ down; it lost its turgidity, and becamo flacI cid, causing the mass to • settle down. Tho I temperature also steadily fell. It w'as pointed 5 out that the decomposition of tho protein, 1 which had also been accelerated by tho riso ! in temperature, could continue oven after : tho cell was dead, becauso tho enzymes, when onco formed, were not dependent on tho ■ life of the coll—in other words, it was an \ autolytic' decomposition. Some of the pro- '• ducts formed inhibited the development of ' mould, and the general conditions obtaining in the silo'-were unfavourable to putrefaction.