140 ANNUAL EEPORTS OF DEPARTMENT OF AGRICULTURE. 



INFECTIOUS ABORTION OF CATTLE. 



The most important result of the station's work on the subject of 

 infectious abortion of cattle during the year is that positive evidence 

 has been obtained that the placentas of cows which have aborted 

 are sometimes infected with abortion bacilli at subsequent normal 

 parturition. This means that it is easily possible for abortion dis- 

 ease to find its way into previously clean herds through the agency 

 of seemingly normal cows of which the history relative to abortion 

 disease is not known. 



Tests have also been made to determine whether a recrudesence of 

 abortion bacilli occurs in the sexual organs of cows which have at 

 some time aborted during the monthly estrual period. Such tests 

 have so far proved negative. 



Further observations have shown wide variations relative to the 

 occurrence of the bacillus of infectious abortion in the milk of cows 

 which have aborted. Some cows continue to produce infected milk 

 for years ; others for shorter periods of time ; some produce such in- 

 fected milk intermittently; and the milk of some entirely escapes 

 becoming infected. The relation between these variations and the 

 power of the milk and blood serum of the cows to agglutinate abor- 

 tion bacilli has received some attention, and further work on this 

 subject is contemplated. 



OTHER WORK. 



Comparative feeding tests with raw, pasteurized, and boiled milk 

 have been continued. When the milk of a foreign species is sub- 

 stituted for the natural milk of a species as food for its unweaned 

 young, the results with an almost germ-free raw milk are about equal 

 to those obtained with equally good pasteurized milk, and the results 

 with boiled milk are somewhat better. 



Several tests have been made in the course of the year regarding 

 the commercial tuberculin sold for veterinary use under Federal 

 licenses and permits. With one exception all samples were found to 

 be satisfactory. 



During the year the usual number of guinea pigs, rabbits, etc., were 

 raised for the use of the scientific divisions of the bureau and a num- 

 ber of minor investigations made which require no special attention 

 at the present time. 



PUBLICATIONS. 



Sixty-two new publications, comprising 1,299 printed pages, were 

 issued or contributed by the bureau during the fiscal year. These 

 included 12 Farmers' Bulletins, 10 Department Bulletins, 7 papers 

 in the Journal of Agricultural Kesearch, 13 issues of Service and 

 Eegulatory Announcements, and 20 miscellaneous pamphlets. The 

 bureau also furnished material for numerous articles in the Weekly 

 News Letter and the Departmental Circular. Several papers were 

 also contributed to outside scientific and technical publications. In 

 addition 88 orders in the nature of regulations were issued and a 

 number of former publications were reissued. 



