196 STATE BOARD OF AGRICULTURE. 



(b) Do the organisms contained in the vaccine persist in the tis- 



sues of the animal body and if so how long? 



(c) What effect does the vaccine treatment have on an existing 



carrier state in the animal? 



(d) When is the most favorable time to administer the treat- 



ment (non-pregnant or pregnant)? 



(e) Does the treatment have any effect upon the health of the 



offspring? 



4. What are the factors involved in the premature expulsion of the fetus, 

 due to Bad. abortus (Bang)? 



5. Does the organism lie dormant in heifers which were infected at birth 

 and invade the uterus after conception? 



6. A rapid method for differentiating between virulent and non-virulent 

 strains of Bad. abortus. 



7. Swine Abortion. 



There were received during the year 521 samples of blood (bovine) for 

 diagnosis of infectious abortion, of which 200, or 37.6 per cent, were positive 

 and the remainder negative. 



There were also received 10 samples of blood from swine for diagnosis of 

 porcine abortion (Bad. abortus) of which 5, or 50 per cent, were positive and 

 the remainder negative. [I. F. Huddleson.] 



Dr. Stafseth took up his duties about a year ago immediately upon his re- 

 turn from a leave of absence in Norway and has pursued his studies with 

 enthusiasm, vigor and skill. He is devoting one-third of his time to teaching 

 and the remainder to the projects discussed below. For the good of the State 

 in general and of poultry husbandry in particular he should have abundant 

 assistance. 



REPORT OF RESEARCH ASSOCIATE H. J. STAFSETH 



The Experiment Station work carried out since my return to the College 

 in the latter part of July, 1921, may be divided into three classes, namely^ 

 research on poultry diseases, miscellaneous diagnostic laboratory examina- 

 tions and field work. 



I. Poultry Diseases. — Due to a general demand from the poultry breeders 

 in the State chicken pox and bacillary white diarrhea have received special 

 attention. A vaccine prepared according to the method employed by J. R. 

 Beach, of the Cahfornia Station, was tried on a flock of over 4,000 chickens, 

 one-half of the flock being vaccinated and the other half left as control. The 

 results were such as to discourage the use of this vaccine because of an in- 

 crease of the internal form of the disease in the vaccinated flock shortly after 

 the inoculation. It may be noted that the disease was quite prevalent in the 

 flock at the time of vaccination and that the flocks showing the greatest in- 

 crease in the diphtheritic form of the disease after the injection of vaccine 



