AGRICULTURAL RESEARCH IN NEW HAMPSHIRE 49 



the results. A chemical method for determining cholic acid has been tried 

 with satisfactory results, and the method is now ready for application to 

 experimental material. 



The growth results obtained on the experimental rations show that 

 there is no relation between the incidence and severity of lesions and 

 growth obtained. How^ever, field reports indicate that in many cases of 

 unthriftiness in growing chicks, there is a marked incidence of gizzard 

 lesion. Many cases of lack of proper development are being attributed to 

 gizzard lesions. It appears that at present sufficient information is not 

 available to distinguish between cause and effect under field conditions. 



R. C. RiNGROSE, E. F. Waller, T. B. Charles. 



S. R. Shimer, H. a. Davis 



Pullorum Investigations 



The rate at which Pullorum disease will spread among adult birds by 

 means of pen contact was determined. Fifteen birds, reacting to the agglu- 

 tination test for Pullorum disease, have been kept in contact with about 

 an equal number of birds which were originally negative. W'eekly blood 

 tests were run on all these birds until reactors appeared among the negative 

 group. Monthly tests were continued after this time. 



Eight birds have been fed broth cultures of Salmonella Pullorum. 

 These were blood tested every third or fourth day following the feeding. 

 At the end of two weeks they were given a complete cultural examination. 



After 52 days of pen contact, two out of the 14 negative birds showed 

 an agglutination titre for Pullorum disease. After 72) days one more re- 

 actor appeared. No more consistent reactors were found although some 

 birds gave a weak or questionable reaction on one or two tests. At the 

 tenth month, nine birds of the original 14 negatives were still alive. Three 

 of these are showing a definite blood reaction. 



Eight to 10 days following the feeding of Salmonella Pullorum in broth 

 culture, seven of the eight birds first showed a reaction. Upon culture the 

 organism was isolated from six of the seven reactors. Usually only one 

 or two of the eight organs cultured in each bird gave us a positive culture. 

 The spleen was the most consistent. 



After 50 weeks of pen contact, 17 of the remaining 21 l)irds were 

 killed and examined. Eight of these were from the original negative birds 

 and three of the eight had been showing consistently positive agglutina- 

 tion reactions since the seventy-third day. The other five have been con- 

 sistently negative. 



Of the three originally negative birds which developed a positive 

 blood reaction, two showed typically afi^ected ovaries and Salmonella pullo- 

 rum was isolated from these birds. The other one showed a chronic peri- 

 tonitis only and the organism was not recovered. Of the five birds which 

 remained negative on blood test throughout the year, one exhibited lesions 

 and the Pullorum organism was recovered from it. 



The nine birds of the positive group were all showing an agglutina- 

 tion reaction at the time they were destroyed. Four of these birds con- 

 tained no lesions and no pathogenic organisms were recovered from them. 

 One bird had a few angular, cheesy ovules but no organisms were re- 



