214 TECHNICAL BULLETIN 10 



An initial injection of 1 cc. was given to 80 birds of the pen, selected prom- 

 iscuously, and 32 birds remained uninjected as controls. All birds were laying 

 well prior to the outbreak of the infection. Both the injected and control 

 groups averaged 43 per cent production at the time the first symptoms of 

 the disease were noticed. Three days prior to tiie first injection tlie egg pro- 

 duction of both groups dropped to 18 per cent. Fifty per cent of the total 

 number of birds showed symptoms of one or more forms of the disease. There 

 was no appreciable decrease in number or extent of lesions or increase in 

 egg production of both groups during tlie next few days. The infection ap- 

 peared to be arrested, however. Nine days following the first injection, a 

 second one of the same dose was given. Three days afterward the injected 

 group of layers improved in general condition and the egg production liegan 

 to increase gradually. The condition and production of tlie control group 

 remained at a standstill. These results were evident in the same proportions 

 for the following two weeks, at the end of which time the last reading was 

 taken. The injected group had reached 41 per cent egg production and the 

 control group averaged 3-5 per cent. Lesions of the disease persisted, however, 

 in all birds, but were somewhat less extensive in type. 



In estimating the percentage of egg production care was taken to consider 

 factors other than disease, which would tend to influence it. 



Results. 



The administration of the autogenous bacLerin was followed by an improve- 

 ment in the general condition and production of the injected grouj). No 

 diminution in numlter or extent of the lesions was noted. Local treatment of 

 the lesions would probably have served the purpose. 



Flock 2. 



An autogenous bacterin was administered to a second flock affected with 

 avian diphtheria. The following organisms, which were used to make the 

 bacterin, were isolated from tyjiical cases of the affection: Staphi/lococci 

 aureus and albus, Gaffkya (Staplit/lococcud) tetrageiia, a gram negati\e, short 

 rod, bi-polar staining bacillus, and an organism of the Escherichia group, 

 typical of Escherichia schaefferi. 



A severe infection of a similar nature had existed in these same pens dur- 

 ing the previous season. At the time of the injection a moderate degree of 

 the infection was present in the birds of houses 1, 2, and 3. One injection of 

 1 cc. of the bacterin, having a concentration of 2,000,000,000 organisms per cc, 

 was given each bird. Previous to the treatment the egg production had 

 dropped to 40 per cent. From four to six weeks later when final readings 

 v.'ere made the production had increased to 66 per cent. House 1 contained 

 2.8 per cent injected birds showing mild symptoms of the disease as opposed 

 to 11 per cent of the non-injected birds or controls in the same condition. 

 House 2 showed 12.3 per cent infection in injected birds and 30 per cent in- 

 fection in the controls. House 3 showed 5.4 per cent infection in injected 

 birds and 41.7 per cent infection in the controls. No attempt was made to 

 treat the symptoms of the disease. 



Results. 



One injection of the autogenous bacterin arrested the course of the infection 

 and brought about an increase in egg production. 



Flock 3. 



A third flock of 2,000 birds was injected, each bird receiving 1 cc. of an 

 autogenous bacterin consisting of Staphylococci aureus and albus, and Pseu- 

 clomonas aeruginosa. The bacterial concentration in this instance was but 

 500,000 organisms per cc. Complete data on the results of the treatment were 



