GLOSSARY. 139 



Vaccine. See bacterin. 



Vesicle. A small elevation of the skin containing serum. 



Vacuole. A cavity in the protoplasm of a cell. 



Virus. An animal poison capable of producing disease. 



Widal reaction. A blood-test for the detection of typhoid 



fever. 

 Wassermann reaction. A blood-test for the detection of 



syphilis. 



