86 Kansas Academy of Science. 



termed pathogenic bacteria. Even now some question has 

 arisen as to whether bacteria should be classed solely among 

 plant life. At any rate, bacteria are extremely minute. Only 

 the highest power of the microscope can detect them. For 

 them a pin point would make a plateau. In some species 15,000 

 to 20,000 could stand "shoulder to shoulder" in a straight line 

 and still be within the limits of an inch. One million would 

 not weigh a gram. 



No other species of life forms are so ubiquitous. Earth, air 

 and water are the abodes of countless billions. Even snow and 

 ice are their rendezvous. One pint of milk contains millions. 

 We drink and inhale thousands upon thousands daily. 



Bacteria propagate by simply dividing. Should one divide 

 to form two new lives, let us say every hour, then 16,613,376 

 would be the number of progeny at the end of twenty-four 

 hours. It has been estimated that a cholera germ divides 

 every twenty minutes. At this rate five quintillions could 

 claim lineal descent from this prolific ancestor in twenty-four 

 hours. If all bacteria were permitted to indulge in such pro- 

 lificacy, there would be no room on the face of the earth for 

 other life forms. Fortunately, environment, competition and 

 food supply do not permit of this luxuriant and riotous growth. 



Only relatively few bacteria are pathogenic to the human 

 body. Otherwise human life would be impossible. Many 

 species are among man's greatest industrial servants. They 

 till the soil; they serve man in the jute and flax industry; they 

 help to tan ; they put aroma into tobacco ; wine, beer and 

 vinegar are the products of their activity. Luscious fruits, 

 cheese and butter are flavored by them. Even our daily bread 

 is a product of their noteworthy labors. 



Pathogenic bacteria, to repeat, are those members of this 

 important group of life which are destructive to animal life. 

 They flourish and multiply in the protoplasm of animal life. 

 When once an entrance is made into the living flesh they begin 

 to multiply and destroy that in which they grow. 



The pathogenic bacteria, as a rule, are classified according 

 to their forms. The slightly elongated, straight, rod-like forms 

 are termed bacilli. If the elongated ones are spirally shaped, 

 then they are called spirHli. Many species of bacteria are 

 spherical in outline, and are known as cocci. 



