68 a EXPERIMENT STATION. [Jan. 



the method a niimber of birds was selected from a flock in which 

 there was every evidence to show that there were many indi- 

 viduals harboring infection and producing eggs containing Bac- 

 terium pullorum^ which, when incubated, produced chicks that 

 soon succumbed to an attack of white diarrhoea. Application of 

 the agglutination test to this part of the flock, previously leg- 

 banded for identification, and the subsequent elimination of 

 every individual showing symptoms of infection, gave most 

 gratifying results in the season's hatch of chicks. Of 1,000 

 chicks hatched from eggs of the tested hens, not one died of 

 white diarrhoea. The previous season, before the bearers of in- 

 fection had been eliminated from the flock from which eggs 

 were saved for hatching, only 200 chicks, of 2,000 hatched, 

 survived the ravages of disease, 1,800 dying of B. pullorum in- 

 fection. This line of work has been carried on in the depart- 

 ment by Dr. G. E. Gage and his assistants. 



The hog cholera investigations were started in January, 

 1913, in co-operation with the Massachusetts Department of 

 Animal Industry, and are in progi'ess at the present time. Since 

 the above date many experiments of a strictly scientific char- 

 acter have been conducted at the experiment station, and also 

 practical tests made in several different herds of hogs, to de- 

 termine the value of anti-hog cholera serum as a cure and pre- 

 ventive of hog cholera. During the period that the work has 

 been in progress no less than 3,283 hogs, on fifteen different 

 farms in the State, have been treated. While the results have 

 not been uniform in the different herds, they have, on the whole, 

 proved satisfactory, and promise eventually to provide a method 

 for the protective treatment of hogs against cholera infection. 

 Little or no curative effect has been observed from the use of 

 serum on hogs actually suffering from cholera. 



