98 THE STORY OF THE BACTERIA. 



diphtheria, when in the fresh condition, come 

 in contact with the mouths or air passages of 

 healthy persons, they may set up the disease. 

 This is because the material composing the 

 membranes may contain large numbers of the 

 living, virulent germs. It is furthermore known 

 that the poison of diphtheria may linger for long 

 periods in rooms where the disease has occurred, 

 and may be conveyed on the clothing of per- 

 sons who have come in contact with the sick. 



Now in this, as in the other bacterial dis- 

 eases which we have studied, if all the material 

 which is cast off and discharged from the body 

 were at once received into strong disinfecting 

 solutions or burned, so that the germs might 

 be killed, the disease would have little tendency 

 to spread. But if, as is too often the case, the 

 discharged particles are allowed to collect on 

 handkerchiefs, or bedding, or clothing, or on 

 the floors, they dry and finally become ground 

 up and mingle with the dust, and as the germs 

 are not killed to any great extent by the dry- 

 ing, when the dust is inhaled it may, if the 

 individual be in a favorable condition for its 

 development, grow and induce the disease. 



