Agricultural Research in New Hampshire 53 



as was done during the previous year. There were 32 swab cultures made 

 from eight birds giving a positive agglutination titre to pullorum disease. 

 All of these cultures were negative to Sahnonella pidlonmi. 



Apparently reacting birds are not at all consistent in discharging Sal- 

 monella pullorwi? organisms in the feces. Exposure to the causative or- 

 ganism will readily produce Pullorum Disease in adult birds. 



A. C. CoRBETT, F. E. Allen 



Anthelmintics in Poultry 



A total of 18 compounds from the group known as sulfones were 

 tested on two-week-old chickens to see if they would control or prevent 

 coccidiosis. Of this group 13 had no protective value, four were rated 

 as fair, two were toxic when fed over a period of time, and one was con- 

 sidered as good on two trials. 



Six compounds were tested as anthelmintics against the common, 

 large, round worm of chickens. One of these, a stabilized nicotine com- 

 pound, was found highly efficient, but the dosage had to be controlled 

 very closely. 



This same nicotine-bearing compound, when diluted with wetable 

 sulphur, was found to be an excellent lousicide for chickens. The residual 

 effect lasted long enough to destroy the }'oung lice as thev were hatched. 

 Four commercial louse powders \\-ere purchased and comparative trials 

 made. The experimental compound was superior to all four in both the 

 initial kill and in the residual effect. It ^^■as equal to, but not superior to, 

 DDT when used in the same proportion and Vvith the same diluent. 



Toxicity trials with DDT were made on chickens, rats, and rabbits. 

 Chickens are not as susceptible to DDT when taken internally as are the 

 tw o species of mammals. It did not remove the ascarids or caecal worms 

 from these birds. 



E. f. A^^aller 



Contagious Indigestion (Blue Comb) 



Twelve poultry flocks containing 44.000 birds were inoculated with 

 the chick-embryo-prepared vaccine. Eight of the 12 farms reported no 

 trouble from blue comb. One farm reported the usual outbreak without 

 resorting to laboratory examination and diagnosis. Of the remaining three 

 farms one reported one case in 2500 pullets, the second 18 cases in 1600 

 pullets, and the third only two cases out of 3300 inoculated birds. 



During the ^\■inter, sufficient vaccine was produced by the egg- 

 embryo a method to inoculate 40.000 to 45,000 birds in 1945. 



F. E. Allen 



SOILS 



Methods for Controlling Erosion on New Hampshire Potato Farms 



During 1944, for the second consecutive year, the winter rye cover 

 crop plots outyielded the plots which were left bare over the winter. The 

 increase in yield of U. S. No. 1 potatoes was 17.2 per cent. Run-off soil 

 losses during the year, although relatively low, were almost twice as great 



