RABIES OR HYDROPHOBIA 231 



from rabies has been greatly reduced by this method 

 of active immunization. At present there is no very 

 accurate laboratory diagnostic test in rabies. The 

 development of the symptoms must be awaited to 

 make the diagnosis in people bitten by rabid animals. 

 The ordinary disinfecting dressings of bichloride of 

 mercury and carbolic acid solutions are worthless for 

 the bites of rabid animals. It is necessary to use 

 the actual cautery or fuming nitric acid in order to 

 certainly remove rabies virus from a wound. 



Yellow Fever. This is an acute infectious disease 

 chiefly of tropical countries, characterized by great 

 prostration, severe pains, hemorrhages, and jaundice. 

 The cause is not known. The disease is transmitted 

 by the mosquito called Stcgomyia calopus, which takes 

 some of the infective blood from a patient and trans- 

 mits it to another person. The virus is in the patient's 

 blood in a condition in which the mosquito can take it 

 during only the first three days of fever. Some cycle 

 of development of the virus takes place in the mosquito 

 because the insect is only capable of depositing it in 

 a bite when twelve days shall have elapsed since it 

 bit a yellow-fever patient. More than that, five days 

 elapses between the bite of the mosquito and the ap- 

 pearance of the virus in the patient's blood. Because 

 of these facts the modern conception of yellow fever 

 supposes a protozoon as the cause. There are no 

 laboratory diagnostic measures nor as yet any specific 

 treatment. The spread of yellow fever is prevented 

 by destroying the breeding places of the mosquito, 

 a difficult thing, since this insect breeds in lowlands 

 and bushes and in houses. It bites usually in the late 

 afternoon. 



