HEALTH AND DISEASE OF POULTRY 569 



contaminated with infected droppings. On this point there is no 

 direct evidence, but in view of the fact that infected and nonin- 

 fected hens have been kept in the same pens for many months with- 

 out any apparent spreading of infection, it seems highly improbable 

 that the organism is conveyed from adult to adult in this manner. 



The question also naturally arises, may not the male bird carry 

 the organism from one hen to another? The same course of reason- 

 ing may be followed here as in the previous instance, and although 

 the evidence is not conclusive, it is quite probable that the organism 

 in question is not carried in this way. Whether or not adult male 

 birds may be infected with Bacterium pullorum is another matter 

 which is still undecided. 



Should the possibilities of the transmission of Bacterium pul- 

 lorum from hen to hen, and through the agency of the male birds, 

 be actually eliminated, there is apparently but one explanation for 

 the presence of the organism in question in the ovaries of adult fe- 

 males. It has been demonstrated that chicks may have the disease 

 when hatched, or acquire it very soon after hatching. The infected 

 female chicks which survive the disease continue to carry the organ- 

 ism in their bodies, not in the various organs, as when they are young 

 and visibly affected, but locally, as in the ovary. In other words, 

 such chicks have become permanent bacillus carriers. 



Summary. In order to avoid possible confusion the term bacil- 

 lary white diarrhea has been applied to that form of disease of young 

 chicks which is caused by Bacterium pullorum. This is the disease 

 commonly called "white diarrhea" by the poultrymen of New Eng- 

 land. 1 The original source of infection is the ovary of the mother 

 hen. 2 Eggs from infected hens contain the organism in the yolks. 

 3 Chicks produced from infected eggs have the disease when 

 hatched. 4 The disease may be spread through the medium of in- 

 fected food and water. Hence normal chicks may acquire it by pick- 

 ing up infected droppings or food contaminated thereby. 5 Infec- 

 tion from chick to chick cannot, apparently, take place after they are 

 three or four days of age. 6 As a rule, infected chicks make less 

 satisfactory growth than those that are apparently normal. For 

 sometime they appear stunted and weak, but may eventually under- 

 go more or less complete development. 7 The female chicks which 

 survive often harbor the infection and may become bacillus carriers. 

 Infection in the breeding pens is perpetuated in this manner. 8 

 In all probability infection does not pass from adult to adult. 9 

 Infected hens are apparently poor layers, especially in their second 

 and subsequent laying seasons. 



Practical Suggestions. It is of the greatest importance that the 

 poultryman learn to recognize bacillary white diarrhea, both through 

 external symptoms and post mortem appearances of diseased chicks. 

 The mere discharge of whitish material from the vent is not in itself 

 proof that the chicks are affected with this specific disorder. 



Infected hens should be eliminated from the breeding pens. 

 Such elimination is made possible by pedigree, records of chicks. If 

 the eggs from the different pens are hatched separately, and the 



