737 



Contribution to the study of fermentations of manure, T. Schlbs- 

 ing, sr. and jr. {Ann. Af/ron., IS {18!J:J),pi}. 5-18). — lii maiiiiie pilod in 

 iieai)s two kinds of leactiou take place. In the part wliere air (;ircu- 

 lates freely a lively combustion jjjoes on, due to the action of aerobic 

 microbes; carbonic acid is evolved in lai'^e ([uantities; and the tem- 

 perature is raised considerably. In the part wiiere free access of air 

 is impossible, anatirobic microbes are active, setting- free marsh gas, 

 hj'drogen, and carbonic a(;id,bnt ])rodncing nuich less heat. This snb- 

 ject has already been investigated by Deherain and Gayou. Recent 

 work by the authors is reported in detail. 



(1) Combustion with access of air, microbic and purely chemical. — 

 "When manure as well as other organic matter is piled in mass with 

 access of air the temperature gradually rises. This elevation of tem- 

 perature seems to be due at tirst to the action of microbes, but it 

 increases until the microbes are destroyed, and it is sufficiently high to 

 enable the purely chemical combustion to go on unassisted. The anthor 

 undertook to determine the exact temperature at which microbic action 

 ceases. The method pursued for this purpose was to maintain at a 

 constant temperature two lots of maiuire, one sterile and the other 

 inoculated, and to pass slowly through each a continuous current of air, 

 which was measured. The combustion was measured by the amount 

 of carbonic acid evolved in each case. Five hundred or 1,000 grams of 

 the moist manure finely divided and carefully mixed was introduced 

 into metal cylinders, fitted with covers which could be soldered on. 

 The cylinders were provided with lead tubes for the entrance of the 

 air and the exit of the gaseous products. For the lot which was to 

 remain sterile the entrance tube was provided with a glass tube plugged 

 with a germ filter L*0 to 25 cm. long. All the lots were sterilized at the 

 same time by being kept for an hour in an oven at 115° C. 



In the first series of tests inoculation was accomplished l)y withdraw- 

 ing the material from the cylinders for a few moments immediately after 

 sterilization and adding a few centimeters of a water extract of non- 

 sterilized manure. The amount of air introduced into the cylinders 

 in a given time was accurately determined. This amount was varied 

 at different times as the intensity of combustion demanded, the object 

 bi'ing to kee]) a considerable excess of oxygen present, and to main- 

 tain a proi)ortion (1 to li per cent or less) of carbonic acid gas which 

 could be accurately determined. Rapid and exact determinations of 

 the latter were made by an apparatus specially devised for the ]uirpose. 

 All results are calculated to grams per kilogram of dry manure. The fig- 

 ures for the sterilized lots represent the purely chemical combustion; 

 those for the inoculated lots, the sum of this combustion and that duo 

 to the ferments. The first experiment was made with fresh cow 

 manure, rich in excrement, and containing 80 per cent of water. The 

 temperatures in the case of different lots were 30°, 40°, and 50° C, and 

 the experiment lasted 35 days. Up to the eleventh day there was no 

 marked difference between the two lots, for the combustion was very 

 21820— :N^o. 10 6 



