Minnesota Plant Life. 115 



such as bullet-wounds, commonly undergo bacterial infection 

 after which pus forms and, in serious cases, blood poisoning may 

 follow. With the increase of humanitarian methods in warfare 

 the time may come when sterilization of bayonets and swords 

 will be insisted upon under the laws of nations, thus diminishing 

 the mortality from wounds in battle. To-day, unless it were for 

 the modern knowledge of bacteria and their habits, surgery 

 would be as rough and ready and generally fatal as it was a hun- 

 dred years ago. 



Light-producing bacteria. Regarding light-producing and 

 heat-producing bacteria there is little necessity to add anything 

 to a mere mention of their occurrence in the state. It is true 

 no ocean bounds the Minnesota of to-day and glows during the 

 activities of light-producing bacteria, but sometimes upon rotten 

 logs or upon damp places in the forest a faint phosphorescence 

 is visible which may be attributed to the presence of light-pro- 

 ducing germs. This powder of illumination, however, exists in 

 some higher fungi, so one cannot be sure that the dim radiance 

 of decayed logs in the forest is due to bacteria unless a careful 

 examination be made. 



Heat-producing bacteria. The heat-producing bacteria, 

 while they are, like all the rest, invisible, are known by their 

 works, and their peculiar habits are tacitly recognized by the 

 insurance companies which send inspectors to see that cotton 

 wastes and refuse are not allowed to accumulate where they 

 might be ignited by "spontaneous combustion." The impres- 

 sion should not be received that all forms of spontaneous com- 

 bustion are of bacterial origin. Some are, however, and the 

 power which bacteria of this kind have of raising the tempera- 

 ture in a mass where they are growing has been clearly demon- 

 strated. 



Color-producing bacteria. Turning now to the examination 

 of color-producing bacteria much might be said, for this is a 

 group of considerable interest and importance. In the middle 

 ages and in regions where science has not yet dispelled the 

 clouds of ignorance and superstition, many men have lost their 

 lives on account of the appearance of red bacteria that excited 

 the fears of those who saw them. The phenoiiienon of "blood- 

 spots" on linen which has been. lying in damp places, or upon 



