18 



the fermentation ceases, the oxygen having been used up 

 and the interstices becoming charged with carbonic acid 

 gas, further action is suppressed, the mass gradually cools, 

 and when opened will be found to contain " sour silage." 



If, on the other hand, the silo is filled gradually and 

 weighted less, considerably more air will be present and a 

 higher spontaneous heating will occur, 50 degrees C. to 70 

 degrees C = 122 degrees F. to 160 degrees F. At this 

 temperature the lactic acid bacteria are in a more suitable 

 temperature for their growth than are the others mentioned 

 as taking place in the production of " sour silage/' They, 

 therefore, so to say, outstrip their competitors in the 

 struggle for existence, and, becoming supreme, only lactic 

 acid is produced to any extent. Such silage is almost free 

 from volatile acids, and possesses a somewhat sweetish 

 smell and an aromatic sweet flavour. The name " sweet 

 silage " is given to this kind. Misleading, for it contains 

 only about half per cent, of lactic acid. 



If the temperature of the heap rises immoderately over 

 70 degrees C. = 160, degrees F. the fodder is burned, and 

 the silage loses its value, either altogether as a food, or the 

 palatibility and digestibility is lowered. Should it be ob- 

 served that the temperature is rising rapidly near to this 

 degree, the pressure should be increased and the activity of 

 the heat-producing germs is consequently diminished. 

 (Water may be poured on in urgent cases.) The tempera- 

 ture is lowered or raised by respectively increasing or 

 lessening the amount of pressure. The temperature should 

 be that most favourable to the lactic acid bacteria if " sweet 

 silage" is desired, lower if "sour." It must be understood that 

 silage cannot be prepared by either 'of these ways without 

 certain losses occurring, which, to our present knowledge, 

 are inseparable from the process. The increased tempera- 

 ture, the evolution of carbonic acid gas, and the formation 

 of acids, are caused by the decomposition of the carbo- 

 hydrates in the fodder; so, also, the acid-forming organisms 

 consume a quantity of albuminoids, breaking them up into 

 substances of a low nutritive value. But," although this 

 sacrifice of some constituents appears to be necessary for 

 the preservation of the rest, it should be our endeavour to 

 reduce that loss to its very minimum. 



Special instruments are sold for taking the temperature 

 of silos. One of those not being procurable, a piece 

 of piping long enough to reach to the bottom of the silo is 

 stopped up at one end and a spike fixed on. It is driven 

 down through the silage, and a thermometer, registering up 

 to at least 160 degrees F., is lowered down the inside of the 

 tube by means of a string. It is allowed to stand for some 

 time, and then pulled up and read at once. 



