KEPORT OF THE SECRETARY OF AGRICULTURE. XIX 



ries, as itemized below. The demand for this preventive is steadily 

 increasing, and the summarized reports of 2,000 cattle owners testify 

 to the great efficienc}^ of the preparation in reducing losses from black- 

 leg to a minimum. It is conservatively estimated that the annual loss 

 from this disease when no preventive measures are taken amounts to 

 about $6,000,000. This estimate is based upon the reported loss of 

 fi'om 10 to 25 per cent of all young stock in the vast districts of this 

 country where blackleg prevails. 



So far as can be judged at the present time the loss after vaccina- 

 tion during the past year has been less than one-half of 1 per cent. 



Since the beginning of the distribution of blackleg vaccine in Au- 

 gust, 1897, the total number of doses furnished to the cattle raisers of 

 this country amounts to 1,711,900, and the indications are that between 

 2,000,000 and 2,500,000 doses will be required to supply the demand 

 during the fiscal year ending June 30, 1901. 



The distribution for the year covered by the present report in- 

 cluded thirty -seven States and three Territories. 



The biochemic division has made and distributed 10,722 doses of 

 mallein for testing horses for glanders. The greatest part of this was 

 supplied to the War Department, while small amounts were distrib- 

 uted in twelve different States. It has also made and supplied to State 

 authorities 33,100 doses of tuberculin to be used for testing cattle for 

 tuberculosis. 



THE PREVENTION OF TUBERCULOSIS. 



Tuberculosis is the most prevalent and most destructive disease 

 affecting mankind and the domesticated animals. Among farm stock, 

 cattle and swine are most often affected. During the last twenty years 

 there appears to have been a great increase of animal tuberculosis in 

 the principal countries of Europe, and unfortunately in those countries 

 from which our breeders desire to obtain animals for the improvement 

 of their stock. 



While this disease exists in parts of the United States, it is yet 

 limited as to territory, and even in the worst infected districts there is 

 a much smaller proportion of the cattle and swine affected than is found 

 in European countries. 



Modern investigation.s show that tu])erculosis is produced by a spe- 

 cific germ, the Bacillus tuhtrculosis^ and that this disease can not 

 develop until the body is invaded by this germ, which can only come 

 from some diseased individual, either man or animal. Being a strictly 

 contagious disease and arising onl}^ by contagion it is important for 

 our stock interests that the law prohibiting the importation of dis- 

 eased animals should be strictly enforced. 



Until the last 3^ear reliance has been placed upon the ordinary phys- 

 ical examination of imported cattle Avhile in the quarantine stations. 



