738 



lively and the liberal supply oi oxygeu at first masked the influence of 

 the ferments, but after that time the combustion was from four to eight 

 times jrreatci- in the inoculated than in the sterile lots. Tiie purely 

 (licniical combustion increased apjtreciably with the temperature. On 

 examininjjj the material at the end of the experiment it was found that 

 the inoculated lots were further advanced in decomposition than those 

 kept sterile, as shown by the appearance and physical condition. Fifty 

 ;,nains of each lot was placed on a filter and treated with wati-r ujitil 

 tlie filtrate showed no further coloration. The residue was dried and 

 weighed. It was found that the fermented lots gave considerably less 

 residue tluin tliose ke]>t sterile. 



The .sec(»n«l i'xpcriiDent, lasting from 23 to 2iJ days, was made with 

 horse manure containing GO per cent of moisture. The temperatures 

 were ~>2'^, .l.S'^, and G(P C The results show that microbic combustion 

 was still active at C<»" (J., on the second day furnishing scv«'iit<*en 

 times as much carbonic a<Md as the purely chemical. These rather 

 remarkable results led to the institution of another exprriment to 

 determine wliethcr thr removal of the material fntm the cylinder for 

 inoculation may not have so improved its ])hysical conditiim as to 

 facilitat*' the production of carbonic a<-id. Tor this purpose the tops 

 of both cylinders were soldcrecl on bef(jre they were placed in the 

 sterilizing oven, and after co<tling a few liters of air which had jtassed 

 through a fiask in which dry manure was shaken up. were rapidly 

 drawn through the cylinder to be inoculated. The same volume of air 

 tillered thnuigh cotton was drawn thiough the cylinder which was to 

 remain sterde. in order that the two might l)e strictly comjiarable. 

 The inoculation by this means proved perfectly satisfactory. Tln^ 

 experiment was made at a temi»erature of (».~>..~)0 V. with horse manure 

 containing 7.{ ]>er cent of moisture, and lasted for .~) days. The results 

 confirmed those already obtained. In a fifth experiment, made with 

 horse maiuire containing 71 per cent of moisture and lasting lor 5 

 days, the temperature was maintained at 70..j° C. There was very 

 litth' diflerence between the sterile sind inocnlated lots, showing that 

 tiu' microbes were not able to act at this temperature, but when the 

 temi)erature was allowed to fall to 73^ and the cylinder reinoculafed, 

 microl)i<- action set in again vigorously. In (»rder to verify these resnlts 

 and lix the temperatures between which microltic actitm ceases, simihir 

 exi)eriments were made at temperatures of Tl'.o- and 81^ C. The 

 results eonlirnuMl tlie preceding. 



The experinn-nts. tiu'iefore, show that at 7.) C. the ai'-robie microbes 

 were still active, but tluit at 71).">^ C. a<tivity had ceased. Instances of 

 fernuMits being active at su<h elevated temperatures are not frequent. 

 The following have been observed: A micrococcus and a bacillus, culti- 

 vated by Van Tieghem at 74-,* and the Ihu'iUus thnmnphilhiso^ Mitpiel, 

 cultivated at 70^ to 71^t. (rlobig has also studied microorganisms 



* IJiil. Soc. Botauique, 28. 



t Auu. do Micrograpliie, No. 1. 



