76 THE BACTERIA UNDER PHYSICAL AGENCIES. 



the vegetative forms die off. This non-ciliated fission fungus is 

 but seldom met with in atmospheric dust, but is very frequent 

 in sewage, and therefore also in sewage -contaminated waters. 

 It is likewise present in the alimentary canal of human beings 

 and mammals. This locality seems to possess a highly suitable 

 temperature for the growth of this saprophyte, although accurate 

 knowledge on the subject is still lacking. When the temperature 

 rises above 50 the medium undergoes putrefaction as a result of 

 the activity of the bacillus. 



Between Bacillus tliermopliilus and the aforesaid cold- loving 

 species there are numerous species forming intermediate links 

 in the chain. In the case of Forster's microbe, already men- 

 tioned, the highest limit of supportable temperature is 35 C., 

 and it cannot retain its vitality when exposed, even for a few 

 hours, to a temperature of 35 to 37 C. GLOBIQ (I.) isolated 

 from garden soil twenty-eight species of bacteria, each of which 

 still developed luxuriantly at 60 C., whilst the minority were 

 able to grow at even higher temperatures. In connection with 

 their occurrence in nature the question of the limits of tempera- 

 ture range of climate within which they can grow is of interest. 

 In this respect great differences were observed, one of them growing 

 as well at 15 as at 68 C., whilst most of the others required a 

 temperature of over 50 C., and one exhibited signs of develop- 

 ment only when the temperature exceeded 60 C. It must there- 

 fore be concluded that, under natural conditions, the reproduction of 

 these organisms proceeds only in the height of summer, when the 

 soil is sufficiently heatt-d by prolonged sunshine. These warmth- 

 loving bacteria are not found in the ground exclusively. LYDIA 

 RABINOWITSCH (I.) isolated from the excrement of various animals, 

 as well as from manures, milk, &c., eight widely distributed species, 

 for which the highest limit of temperature at which growth was 

 possible was found to be 75 and the minimum about 39 C. 

 These organisms are therefore able to reproduce freely in the 

 alimentary canal of warm-blooded animals and human beings. 

 Warmth-loving fission fungi are also not infrequently encountered 

 in sea-water. One example of this is afforded by a phosphorescent 

 bacterium found in the West Indies and described in Chapter xv. 

 under the name of Bacterium plwsphorescens. This inhabitant of 

 the tropics thrives best at 2o-3o C., and ceases growing at 15 C. 

 Living bacteria have also been found in boiling springs, e.g. that 

 discovered by Cortes and Garrigon in the basin of a mineral spring, 

 the temperature of which was 64 C. J. KARLINSKY (I.) in 1895 

 discovered in the hot sulphur springs at Ilidze, near Sarajevo in 

 Bosnia, two species of Schizomycetes which he named Bacterium 

 Ludwigi and Bacillus Ilidzensis capsulatus, the former developing 

 only when the temperature rose above 50 C., and the second 

 producing endospores able to withstand four hours' exposure in 

 water at 100 C. without succumbing. 



