220 BACTERIA, YEASTS, AND MOLDS 



eliminating the infectious organisms. The same is true, 

 probably, of tonsilitis and grippe (Fig. 72). In consump- 

 tion, discharges from the lungs pass into the mouth and 

 are voided in the sputum. It becomes evident, therefore, 

 that here is a disease the contagion of which is found in 

 the sputum and also in the breath exhaled when cough- 

 ing. The ordinary breath does not contain the germs. 

 ^•>'lg, ,In typhoid fever and cholera the most dis- 

 %\e<i tinctive characteristic of the disease is the 

 Fig. 72. Ba- diarrheal discharges from the alimentary canal, 

 cilluscausing and this suggests that the faeces may be the 

 influenza or source of exit of infectious material. Thus, 

 g"ppe' though contagious diseases differ very much 



from each other, it is rarely difficult to determine by 

 observation the method by which the infectious matter 

 leaves the body in the case of any particular contagious 

 disease. The practical fact to bear in mind is that dur- 

 ing the progress of an infectious disease any unusual 

 discharges from the body, mouth, skin, or elsewhere are 

 almost always the means of exit of the parasites, and from 

 such excretions all members of a household should be 

 most carefully guarded. Special attention should be given 

 to the care of the various discharges from the patient, and 

 if this is done the contagion may be reduced very largely, 

 and in many cases be absolutely prevented. 



2. How Disease Germs are carried to and fro 



There are several methods by which infection may 

 be carried from the body of the patient to that of the 

 healthy person. In the case of some diseases it is chiefly 



