BUREAU OF ANIMAL INDUSTRY. 227 



possibility of finding a vaccine or preventive serum for this disease 

 has been suggested b}^ Professor Bang, the further investigation of 

 the specific bacillus will be continued in the iDathological division. 



A great number of pathological specimens have been referred to 

 the division for diagnosis. These have been received from members 

 of the meat-inspection force of the Bureau of Animal Industry, from 

 various State sanitary officials, from practicing veterinarians, or from 

 private parties. In each case a histological and bacteriological exami- 

 nation has been made and the inquirer informed of the results. 



THE EXPERIMENT STATION OF THE BUREAU. 



The experiment station has cooperated with the other divisions in 

 their experimental investigations, bj^ which it has been conclusively 

 determined that the best animals to use for the jDroduction of hog 

 cholera and swine i^lague antitoxic serum are cattle, mainly because 

 of their considerable immunity from inflammatory processes of the 

 kind which are j^roduced in other animals when the cultures of living 

 hog cholera and swine plague germs are injected under the skin. 

 The serum obtained from horses, mules, and donkej^s is fully as 

 potent as that from cattle, but can be jjroduced only at a much 

 greater cost. 



The antitoxine animals during the year supplied about 1,500,000 

 cubic centimeters of blood, which was delivered to the biochemic 

 laboratory, where the serum was collected and prepared for distri- 

 bution. 



A serum for the prevention of the disease known as tetanus, or 

 lockjaw, is being prepared and will soon be ready for use. The exer- 

 cise of the greatest care does not prevent an occasional outbreak of 

 tetanus among antitoxine animals unless measures are taken to make 

 the animals immune from the affection. A perfectly satisfactory 

 immunity is produced by periodic injections of tetaniis antitoxic 

 serum. 



TEXAS FEVER. 



The work on Texas fever has been of two kinds : First, that directly 

 concerning the disease; and, second, that concerning the destruction 

 of the Southern cattle tick. 



In a previous year a number of cattle ticks {Boopliilis hovis) were 

 received from Porto Rico and tested as to their infectious character. 

 Two Northern cattle were exposed to them and seemingly escaped 

 having an attack of Texas fever. During the year just ended two 

 cows and a calf were received from Porto Rico. Blood was drawn 

 from the jugular veins of the cows and injected under the skin of two 

 Northern cows susceptible to Texas fever. The result was that the 

 two Northern cows became affected with the disease. One died and 

 the other is now making a slow recovery. This shows conclusively 

 that Texas fever exists in the island of Porto Rico, and very proba- 

 bly in other portions of the AVest Indies. 



The two cattle which were exposed in a previous year to ticks 

 received from Porto Rico, seemingly without suffering an attack of 

 Texas fever, were turned into a field during the year just ended with 

 several other cattle and infected with noninfectious ticks. When the 

 noninfectious ticks had matured and dropped to the ground, and eggs 

 had been produced and hatched, and the new crop of young ticks 

 began to appear on the cattle, several cases of fatal Texas fever 

 developed. The two animals i^reviously exposed to Porto Rican ticks 

 remained unaffected. From this we may draw two conclusions : First, 



