Figure 3. Bird No. ! — Noninfected Hen; Bird No. II — Infected Hen. 

 Pullorum diseased birds as a rule cannot be differentiated from the noninfected by physical 

 examination. Apparently normal, well-developed birds may be affected with the disease. In- 

 fection in such birds can be detected either by the agglutination test or by bacteriological examin- 

 ation. Refer to questions 4 and 33. 



/&• 



' ^ 



/ 

 / / 



Figure 5. The heart on the left is apparently norma land was removed from a noninfected hen 

 The heart on the right shows enlargement, thickening of the heart sac. and roughened heart 

 surface. S. pullorum was isolated from the pericardial fluid. Refer to question 4. 



(11) 



