BACTERIUM PULLORUM INFECTION IN FOWL. 83 



The Present Status of the Specificity of the Agglutinatio7i Test as a Means 

 of Control of Bacterium Pulloruin Infection in Yoking Chicks. 



During the last few years the agglutination test has become a popular 

 means of recognition in the domestic fowl of those individuals which have 

 contracted Bad. pulhrum infections in chickhood; and conseciuently, as 

 adult productive fowls, may have become, through infections in their 

 ovaries, carriers of infection to the offspring. Several writers have demon- 

 strated that there are certain factors which have influenced the test and 

 which suggest the need of modification of the method in the direction of 

 securing a higher degree of specificity. Hadley suggests that we stand in 

 need of a means of diagnosis which shall distinguish between a latent 

 (presumably ovarian) and a past infection. The data presented up to 

 date indicate that not all adult hens with Bad. pullorum have infections 

 localized in the ovaries; and also that not all infection has its origin in 

 an attack of bacillary white diarrhoea experienced in the chick stage. 

 This point, as Hadlej- suggests, is of less significance in its bearing upon 

 the validity of the results of agglutination tests for Bad. pullorum in- 

 fection than is the question of the specificity of the test. This author as 

 well as others has demonstrated the interagglutinability of Bad. pullorum, 

 fowl typhoid and other antigens in both Bad. pullorum and fowl typhoid 

 serum. Fowls which have been experimentally immunized against dif- 

 ferent t\-pes of fowl typhoid possess serum which agglutinates Bad. 

 pullorum antigens quite as well as it agglutinates its homologous antigen. 

 According to these data the agglutination test for the recognition of Bad. 

 pullorwn infection appears to lose some of its claim to specificity; and to 

 this extent, without carefully going over the results as obtained in field 

 and laboratory co-operating, it may be open to criticism. 



If all operations both in field and laboratory are considered, however, 

 the reader will be convinced that the test yields valuable results. From 

 our work, already reported, during the seasons of 1919-20 and 1920-21, 

 there were only six cases where the anaerogenic type of organism was 

 isolated and the post-mortem examinations revealed the enlarged spleen 

 associated with leukemic conditions. This indicates that, at least so far 

 as this laboratory has been called upon to make examinations, fowl typhoid 

 infections are infrequent. That all infections are localized in the ovary is 

 yet to be proven. It can be said, however, that the ovarian infections 

 are not rare, and when they are present they persist". During the course 

 of the examination of hundreds of eggs for Bad. pullorum infection, only 

 the true aerogenic fonn of Bad. pullorum was isolated. Strains of these 

 cultures, even after four years, maintained this aerogenic property and 

 were maltose-dextrine-dulcite negative. Therefore these studies indicate 

 that fowl typhoid is not transmitted to the egg. In all of our work in the 

 bacteriological examination of young chicks, in all cases showing large 

 unabsorbed yolks, we have been able to isolate only the aerogenic type of 

 organism, and this in hundreds of cases. This shows an apparent lack of 



