72 MASS. EXPERIMENT STATION BULLETIN 449 



The reciprocal mating yields red daughters (with no black in plumage) and white 

 sons. It has not yet been determined whether this "new" factor for dominant 

 white is identical with the well-known dominant white as found in the Leghorn, 

 is an allele of it, or is a new independent factor. 



SEED CONTROL 

 Frederick A. McLaughlin in Charge 



Enforcement of the Seed Law, together with the desire of seedsmen to comply 

 with requirements of this Act, and a growing interest of the public in good seed, 

 has greatly increased the number of service samples sent to the seed laboratory 

 for testing. From July 1, 1947, to June 30, 1948, 6958 service and inspection 

 samples ot seed were received and worked at the laboratory, an increase of 1105 

 samples over the previous year. The laboratory also received and cleaned 101 

 lots of tobacco seed. 



Analysis of inspection samples shows that most seedsmen have complied with 

 label requirements of the Seed Law. A large part of the violations found are 

 technical in nature rather than flagrant. 



Operation of the Seed Law is reported in an annual bulletin issued for that 

 purpose. 



DEPARTMENT OF VETERINARY SCIENCE 

 J. B. Lentz in Charge 



Poultry Disease Control Service. (H. Van Roekel, K. L. Bullis, G. H. Snoeyen- 

 bos, O. S. Flint, F. G. Sperling, M. K. Clarke, O. M. Olesiuk, and E. M. Allen.) 



1. Pullorum Disease Eradication. During the 1947-48 testing season 605 

 flocks (including chickens and fowl other than chickens) were tested in 12 coun- 

 ties. A total of 1,272,547 chicken blood samples was tested, of which 0.10 per- 

 cent were positive. A total of 24,564 blood samples from fowl other than chick- 

 ens was tested. None of these were positive. Sixteen "breaks" were detected 

 and of this number 13 revealed less than 0.5 percent reactors. The majority of 

 the "break" flocks were retested until the flocks obtained a negative status. 

 Non-reacting chicken flocks numbered 476 and represented 1,185,852 birds or 

 97.20 percent of all birds tested. 



The testing results reveal further progress in the establishment and main- 

 tenance of pullorum-free flocks. A more detailed discussion on the pullorum 

 testing work will be given in the Twenty-eighth Annual Report of Pullorum 

 Disease Eradication in Massachusetts. 



2. Salmonella pullorum Antigenic Forms. During the 1947-48 testing season 

 S. pullorum cultures were isolated and typed for antigenic form from 34 birds 

 selected from 20 flocks in the State in which pullorum infection was detected by 

 routine flock testing. Twenty-three birds from thirteen of these flocks were 

 found to be infected with a Standard form of 6". pullorum (IX, XII, XII2 + , 

 Xllai). Six birds from three flocks were found to be infected with a Variant 

 form (IX, XII, Xlhi, Xllai). The remaining five infected birds from four 

 flocks yielded cultures with antigenic characteristics between those of Standard 



