THE MANUFACTURE OF ANTISERA. 489 



diluted serum from the suspected case is placed under the microscope 

 with the live, specific organisms in hanging drop. In the macroscopic 

 method, the serum is added to an emulsion of the killed (heated) bacteria 

 in small test tubes, and the resulting reaction detected with the naked 

 eye. 



The emulsion, suspension or "test fluid" for the typhoid agglutination 

 test is prepared from a pure culture of B. typhosus. The organism is 

 grown for twenty-four hours upon agar slant media at a temperature of 

 37. The growth is then removed from the surface of the agar, placed in 

 sterile, physiological salt solution and the organisms killed by heating on 

 a water bath at a temperature of 60 for one-half hour. The emulsion 

 is then roughly standardized by adding sufficient sterile, physiological 

 salt solution to impart to the fluid the required degree of cloudiness, 

 when compared with certain emulsions. To the suspension of dead 

 typhoid organisms or "test fluid" a preservative, usually formalin, is 

 added and the product is distributed in properly labeled bottles. In 

 conducting the test, the suspected typhoid serum is placed in small tubes, 

 each containing i c.c. of the suspension fluid, in such proportions that 

 the serum is diluted i to 50, i to 100 and i to 200. A flocculent precipi- 

 tate of the dead organisms indicates a positive reaction. 



Suspension fluid for the glanders agglutination test is prepared in 

 practically the same manner as the typhoid test fluid. The glanders 

 organisms are grown on acid agar and the suspension fluid is usually 

 preserved by the addition of carbolic acid. In conducting the glanders 

 agglutination test, the suspected serum is usually placed in the following 

 dilutions : i to 200, i to 500, i to 800, i to 1200, and i to 1800. 



The agglutination reaction has been applied experimentally and prac- 

 tically, with more or less success in the diagnosis of Malta fever, Asiatic 

 cholera, bubonic plague, pneumonia, tuberculosis and other infectious 

 diseases. 



