SWEET ENSILAGE 201 



this was effected exclusively in silos whence the term ensilage, current for this 

 operation in England and France, is derived. 



According to the composition of the raw materials, their water-content and 

 method of treatment, two classes of durable fodder are obtained, viz., green 

 pressed fodder and sour fodder. The main factor determining which of them 

 shall be produced is the height of the temperature attained, as the result of 

 spontaneous heating, in the mass. If this does not exceed 40 C., then the 

 butyric ferments develop along with the lactic acid bacteria, and a sour-smelling 

 product, known as sour fodder, results. More detailed particulars of this are 

 given in the next paragraph. 



If, on the other hand, the thermogenic bacteria develop vigorously in the 

 heap, and thus cause the temperature to rise rapidly to 50 C. and remain there 

 for some time, then the lactic acid bacteria develop by preference, overcome all 

 their competitors, and exert a practically undivided sway. In this case a 

 durable fodder is obtained, which is almost entirely free from volatile acids and 

 devoid of odour, or with a somewhat sweetish smell, on which account it is 

 known as sweet fodder ; though this name is hardly correct, owing to the 

 strongly lactic acid character of the product. A more suitable appellation has 

 latterly been bestowed on it, viz., green pressed fodder. 



This process originated in England in 1885, under the name of sweet 

 ensilage, but through the explanatory treatise written by G. FRY (I.) became 

 known on the Continent, where it was at first styled Fry's ensilage. The 

 numerous investigations to which it was there subjected led to important 

 conclusions, both of a chemical and practical nature, which were fully reported 

 by FR. ALBERT (II.). Nevertheless, from the Fermentation Physiologist's point 

 of view, no advance has been made beyond the general information already 

 given by Fry. On account of this deficiency we are obliged to dismiss this 

 process (important though it is to agriculturists) with merely a very few 

 remarks. 



As the name itself implies, green vegetable substances, such as waste beet 

 leaves, clover, green^maize, &c., are used for the preparation of green pressed 

 fodder. Silos are unnecessary, the materials being stacked in the form of a 

 straw- thatched cottage, tightness of packing being an important feature. By 

 suitable means (e.g. horizontal beams with weighted ends, or similar stack 

 presses) a Continuous heavy pressure is exerted on the stack, the amount of 

 the pressure being a predominant factor influencing the degree of spontaneous 

 heating produced. Should the temperature not rise quickly enough, then the 

 pressure is moderated to admit air more freely to the thermogenic bacteria. On 

 the other hand, if the temperature rises immoderately (beyond 70 C.), then the 

 pressure is increased, the access of the air restricted, and the oxidising activity 

 of the said organisms consequently diminished. The state of the internal tem- 

 perature is observed by means of an ensilage thermometer designed by E. 

 Meissl, the scale of which projects from the side of the stack. In a word, the 

 stack is regulated in such a manner as to ensure the predominance of the lactic 

 acid bacteria, whereby, under normal conditions, a product of a green to olive- 

 green colour, and of an aromatic sweet flavour, is obtained. The structure of 

 the vegetable matters employed is still distinguishable. A sample of this fodder, 

 prepared from crimson clover, contained (according to Bohmer) 71 per cent, of 

 water and about 0.36 per cent, of total acids, of which 0.27 per cent, was lactic 

 acid, and the remainder consisted of butyric acid, acetic acid, valeric acid, &c. 

 In the researches recorded by Fr. Albert the total acids (calculated to dry 

 matter) in a sample of green pressed fodder, prepared from meadow grass and 

 containing 68.4 per cent, of water, amounted to 2.49 per cent., of which 1.89 per 

 cent, was composed of non-volatile acids (lactic acid). 



