ESSENTIALS OF BACTERIOLOGY 



Asporogenic Bacteria. Bacteria can be so damaged that 

 they will remain sterile not produce any spores. This con- 

 dition can be temporary only or permanent. 



Arthrosporotrs. In the other group, called arthrospores, 

 individual members of a colony or aggregation leave the same, 

 and become the originators of new colonies, thus assuming the 

 character of spores. 



The micrococci furnish examples of this form. 



Some authorities have denied the existence of the arthro- 

 sporous formation. 



Resistance of Spores. Because of the very tenacious 

 envelop, the spore is not easily influenced by external measures. 

 It is said to be the most resisting object of the organic world. 



Chemical and physical agents that easily destroy other life 

 have very little effect upon it. 



Many spores require a temperature of 140 C. dry heat for 

 several hours to destroy them. The spores of a variety of 

 potato bacillus (Bacillus mesentericus) can withstand the 

 application of steam at 100 C. for four hours. 



CHAPTER II 

 ORIGIN OF BACTERIA AND THEIR DISTRIBUTION 



As Pasteur has shown, all bacteria develop from preexisting 

 bacteria or the spores of the same. They cannot arise out of 

 nothing. 



The wide and almost universal diffusion of bacteria is due to 

 the minuteness of the cells and the few requirements for their 

 existence. In a drop of water 1,700,000,000 cocci can find 

 space. 



Very few places are free from germs; the air on the high seas 

 and on the mountain-tops is said to be free from bacteria, 

 but this is questionable. 



