| Plates were incubated upright at 30°C for 48 72 hrs and were visually inspected for the formation of precipitin rings. |
| All these functions were attributed to different substances in the serum, and named accordingly as antitoxin, precipitin and agglutinin. |
| A test serum is positive if it forms a specific precipitin line with the antigen and forms a complete line of identity with the control serum. |
| In antibody test against H. capsulatum, the positive immunodiffusion reactions involve one or more specific precipitin bands. |
| The antiserum used for the precipitin reaction was obtained by treating a rabbit with human blood serum. |
| The precipitin reaction, however, has never been applied to actual problems in avian taxonomy prior to the present study. |
