440 MICROORGANISMS 



dishes used by other members of the family; they may get 

 into water supplies or wells, into the milk distributed by 

 dairies, or on fresh fruits and vegetables distributed by gro- 

 ceries and be widely spread through a community. In many 

 such ways the transfer of the organism from the wastes of the 

 sick patient to the food or drink of healthy persons is ac- 

 complished if it is not shut off at its source by the use of 

 disinfectants. 



If the wastes from a typhoid patient are all collected in a 

 suitable vessel and treated with a 5 per cent, solution of carbolic 

 acid for an hour before they are put into the sewer or outdoor 

 vault, and due care is taken by those who attend the patient, 

 there is little chance for further spread of the disease. This 

 sterilization of the wastes needs to be kept up, however, 

 until the patient is known to be free from the organism. The 

 time when a patient is free from the organism after recovery 

 can be determined by a bacterial examination. Some persons 

 recover from the disease and yet carry myriads of the organ- 

 ism for months or even years and may, all the time, be a source 

 of spread of the disease. Such persons are known as TYPHOID 

 CARRIERS. 



We do not have any successful serum treatment for typhoid 

 fever but we do have vaccines which consist of the dead bacteria 

 or materials derived from them that have proved wonderfully 

 successful in rendering persons immune from the disease. 

 Soldiers in the armies are regularly vaccinated against typhoid 

 now and the result is that this disease which was once a prin- 

 cipal danger to the soldier has, in many instances, nearly dis- 

 appeared from the army camps. Vaccination is also widely 

 practised in cases of epidemic outbreaks of the disease among 

 private citizens. The immunity produced either by an attack 

 of the disease or by vaccination is only temporary and so 

 vaccination must be repeated at intervals. 



512. Influenza or Grippe. This very common disease is 

 now known to be caused by a very small rod-shaped bacterium 

 known as BACILLUS INFLUENZA. The disease is of common 



