MORPHOLOGY. 



average sized bacilli to weigh one grain, and 

 that fifteen hundred of the largest bacilli if 

 placed end to end would not reach across a 

 small pin head. Bacteria are single cell plants 

 (unicellular), but this single cell is capable of 

 producing innumerable other cells under favor- 

 able circumstances. Some forms of bacteria Power of 

 move about quickly, through flagella, an Motion, 

 appendage which is lash-like in appearance and 

 by means of which they are made to resemble 

 a form of animal life. Other bacteria are very 

 slow in their movements. 



Weigert* in the year 1877 discovered thai weigert's 

 micro-organisms could be colored by the use of Discovery, 

 aniline dyes, so as to be distinguished from the 

 media in which they are cultivated. Up to that 

 time great difficulties stood in the way of theii 

 successful study, because of their transparency 

 as well as their minuteness. Since Weigert's 

 discovery that they can be colored, many of the 

 peculiarities by which their varieties are deter- 

 mined have been pointed out. 



We have said that one condition necessary tc 

 the growth and development of bacteria is 

 proper soil. A perfectly healthy body with 

 normal resistive power is not favorable soil for 

 the development of disease germs. In such a 

 body certain cells exist which are foes to these 



♦Professor Carl Weigert, anatomist at Frankfort 

 Germany. 



41 



