July 9,1917 Microorganisms and Heat Production in Silage 77 



The general plan of procedure for determining the relative importance 

 of microorganisms and intramolecular respiration of the plant cells in 

 the heating of siloed forage provided checks of different types on 

 microbial activity. Heat production was observed in — 



(a) Normal fermenting forage ; 



(6) Forage treated with a weak antiseptic; 



(c) Forage treated with heat ; 



{d) Heated forage inoculated with bacteria; 



{e) Cured or dried forage. 



Normal fermentation, used as a check, was provided by siloing the 

 untreated forage. When alfalfa was used, 2 to 5 per cent of cane sugar 

 was added to supply an available source of carbohydrate for the 

 ferments. 



Forage treated with a weak antiseptic offered favorable conditions 

 for intramolecular respiration of its tissue cells, while the action of the 

 microbial flora was checked. Two to three per cent of chloroform was 

 used for this purpose. 



The action of both microorganisms and tissue enzyms was prevented 

 by heating the forage for one to two hours at 100° C. In this way all 

 plant enzyms and the majority of the essential microorganisms 

 were killed. Forage thus made inert was treated with chloroform to 

 check the action of any organisms not killed by the heat and those 

 which entered during the siloing of the heated forage. Such treated 

 forage was used chiefly as a control both for heat production and 

 chemical changes. 



Heated forage was also inoculated with a pure culture of the Bulgarian- 

 like organism isolated from silage. 



Cured and dried forage, to which the proper amount of moisture had 

 been added to insure conditions for fermentation, was likewise siloed. 

 Owing to the destruction of large quantities of plant enzyms by drying, 

 such forage offered little or no opportunity for tissue acti\nty. 



Total acidity determinations were made by the method described by 

 Hunter and Bushnell (9). The results are expressed in terms of lactic 

 acid per gram of dry forage. 



EXPERIMENTAL DATA 



Only representative records of the different kinds of forage are 

 reported from the large amount accumulated, as all exhibited the same 

 essential characteristics. The temperature readings in each case are 

 plotted as curves. Figures i to 10, inclusive, indicate the heat-producing 

 ability of the different kinds of forage. The untreated .and inoculated 

 forage all exhibited a marked increase in acid production, while the 

 chloroformed and heated samples exhibited no increase. 



Good clean-flavored silage resulted in every instance from the fermenta- 

 tion of the untreated, green, cured, and inoculated forage. The treated 



