88 MASS. EXPERIMENT STATION BULLETIN 339 



(b) Viability of S. pullorum. Viability studies, which are still in progress, 

 have shown that S. pullorum has remained alive in a dry piece of cloth for a 

 period of four and one-half years. 



(c) Whole-Blood Agglutination Test. During the past year investigations 

 concerning the whole-blood test have been continued in order to improve its 

 efficiency. A change in the technique consisting of more accurate measurements 

 of whole blood and antigen was tried. Limited data suggest that the efficiency 

 of the whole-blood test is increased when a serological pipette is used to measure 

 definite, constant quantities of whole blood and antigen. 



(d) Maltose-Fermenting S. pullorum Strains. During the past six years S. 

 pullorum strains which were retained as stock cultures have been observed to 

 acquire the property to attack maltose. The behavior of these and other strains 

 toward maltose has been studied. It was found that strains which possessed a 

 potential tendency to ferment maltose could be identified by cultivating them 

 in a maltose-peptone solution for a period of time. Some strains acquired this 

 property much sooner than others. Strains undergoing a change in behavior 

 toward maltose would exhibit red and white colonies when plated on a modified 

 Endo's medium (maltose substituted for lactose). Among twelve maltose- 

 fermenting strains studied, only one failed to show white colonies on this 

 medium, suggesting that complete conversion had occurred. Strains that pro- 

 duced both maltose-fermenting and non-maltose-fermenting colonies exhibited 

 only non-maltose-fermenting colonies after being subjected to animal passage. 

 An apparent pure maltose-fermenting strain did not lose this property when 

 subjected to animal passage. 



(e) Pullorum Disease in Turkeys. Pullorum disease was encountered in two 

 turkey flocks during the past year. 



Flock 1. Two consignments of poults ware received from this flock. The 

 clinical history which was reported for the first consignment and the lesions 

 observed were suggestive of pullorum disease. A 25 percent mortality was 

 experienced during the first nine days after hatching. A second consignment, 

 received approximately a month later, represented poults that were hatched 

 on a later date. The poults were approximately five weeks of age and greatly 

 stunted. The sera of five poults were tested with pullorum antigen in three 

 dilutions (1:25, 1:50, 1:100). Three sera produced no agglutination, but two 

 completely agglutinated the antigen in all three dilutions. S. pullorum was 

 isolated from one of the five poults and the serum of this bird was also positive. 

 Incomplete evidence suggests that the infection might have originated in a 

 custom hatchery. When the survivors of the outbreak were approximately six 

 months old their sera were tested with pullorum antigen. Among 118 birds 

 tested 28.81 percent exhibited reactions which varied in degree with a maximum 

 titre of 1 :320. Through the cooperation of the flock owner it was made possible 

 to examine bacteriologically some of the reacting birds which had been dressed 

 for the holiday trade. Cultures were taken from eight birds and S. pullorum 

 was isolated from three. The agglutination titres of the three birds were 1 :20, 

 1:40, and 1:320. A program is in progress to eradicate pullorum infection 

 from this flock through short-interval testing. 



Flock 2. Pullorum disease was diagnosed in two-weeks-old poults which 

 suffered approximately a 33 percent mortality. The history of the consign- 

 ment revealed that losses were confined to a group of 200 poults which had been 

 received from a mid-western state. The balance (1,800) of the flock did not 

 appear to be infected. 



3. Disease Studies in Wild Animals. During the past year the collection of 

 normal and diseased specimens of wildlife has increased. Specimens of ruffed 



