Of the 156 flocks tested this vear, 123 have followed Testing Plan No. 2, 

 19 Testing Plan No. 1, and 14 Testing Plan No. 3. 



Testing Plan No. 2 appears to be the most satisfactory one to the poultry- 

 men and has been most generally followed by them. By adopting this plan 

 both hens and pullets are tested, and this arrangement seems to be what most 

 of the poulti-ymen want. 



Discussion of the Problem Presented by the Bacillary White Diarrhoea 

 Situation in Massachusetts. 



The problem in the control of bacillary white diarrhoea is the elimination of 

 cai'riers of the disease. Upon recovery from the infective process the hen's 

 body, in most cases, probably rids itself of the animate agent. Salmonella pul- 

 lora, which is the single essential cause of the disease. In many cases, however, 

 recovery takes place, but the infecting agent continues to live in the hen's body, 

 where its presence, as a rule, is not indicated by any symptoms. Reference 

 has already been made to the localization of the organism in the ovaries of the 

 hen, and its transmission to the eggs and thence to the chicks hatched from 

 these eggs. Many of these chicks live and become carriers, and thus the 

 vicious cycle of infection continues. Not only through these carriers is the in- 

 fection spread, but in them the disease is kept alive in the interval between 

 bi'eeding seasons. So far as is known, thei'e is no treatment which will rid the 

 bi'eeding hen of this organism and thus prevent it from passing on the disease 

 to its progeny. This indeed is one of the difficult and important problems of 

 preventive medicine. The recognition of these carriers, however, at once ren- 

 ders preventive measures more efficacious and certain. The problem therefore 

 i-esolves itself into detection of the carriers, and this at the present time requires 

 comprehensive serological examinations. One hopeful feature of the problem 

 liowever, is that the number of carriers will diminish proportionately with the 

 luunber of cases of bacillary white diari-hoea. Every improvement in the sani- 

 tary conditions generally will have a tendency to diminish the number of ear- 

 liers of the infection. 



In consideration of the mode of transmission of the disease, the male bird 

 lias not been mentioned as a carrier. At the present time, what part, if any, 

 the male bird plays in the transmission of the disease is not known. The data, 

 however, show that there is an enormous preponderance of females over males 

 among the carriers, which suggests that the male bird plays a negligible part 

 in the transmission of the disease. It is advisable, however, to keep the male 

 birds separate from the females, except during the breeding season, since it is 

 piobable that the male bird may act as a passive carrier in some instances. 



Tt may here be stated that a diagnosis of bacillary white diarrhoea should 

 iiot be made without laboratory aid. It is very doubtful, indeed, whether a 

 diagnosis can be made in the absence of cori*oborative lal)oratory tests. The 

 most important and reliable of these tests are the agghitination reaction in adult 

 birds and the demonstration of Salmonella pullora in young chicks. The aggluti- 

 nation test which is used for the detection of the infection in adult birds, while 

 highly accurate and reliable, is by no means absolute. A positive result is highly 

 indicative of bacillary white diarrhoea, but on the other hand, a single negative 

 result is certainly not proof of the absence of the disease. It is for this reason 

 that consecutive, non-reacting tests are required to establish the fact of free- 

 dom from infection. 



In the case of any infectious disease, a campaign of education is always 

 necessary at the time the disease is l)eing attacked. This has been attempted in 

 the bacillary white diarrhoea work by means of pamphlets outlining well-de- 

 fined control measures, copies of which are sent to those poultrymen who apply 

 for the test. These pamphlets have been very well received, and many poultry- 

 men have cooperated fully in the preventive program there outlined. Had the 



