350 Annual Report for 1911 of Roijal Veterinarr/ College. 



The second fact brought to light by the extensive 

 application of the mallein test in infected studs was that the 

 incubative period of the disease was often far longer than 

 had been suspected. Horses found to be infected by applj^- 

 ing the mallein test to them sometimes developed outward 

 symptoms soon afterwards, but in many cases the reacting 

 animal never became clinically diseased or did not develop 

 external sign of glanders or farcy for months or years 

 afterwards. 



As soon as these facts were recognised it became apparent 

 that it was vain to expect that glanders could be stamped out 

 simply by killing the obviously diseased horses. When the 

 disease broke out in a stud of any size, slaughter of visibly 

 glandered or farcied animals (which was all that the law 

 required except disinfection of the premises) nearly always 

 left one or more horses affected with the disease in its 

 incubative stage. The disease was therefore not eradicated 

 from the stable in which the outbreak occurred, and oppor- 

 tunity was left for its spread to other studs by the sale of 

 some of the apparently healthy but in reality diseased horses. 



It took a period of at least ten years to bring these facts 

 home to the minds of horse-owners, and thus to prepare the 

 way for such an alteration in the then existing Glanders 

 Order as would enable Local Avithorities to prevent the sale 

 of horses affected with glanders in its incubative stage. This 

 alteration was effected in the new Order which came into 

 force on January 1, 1908, and the fruits of it are seen in 

 the Table already given. Under this Order when a case of 

 glanders is detected in any stable, and all the visibly diseased 

 horses have been destroyed, the apparently healthy horses are 

 viewed as suspected animals, and their movement is restricted 

 until the suspicion has been removed by the mallein test. 

 Siich of the apparentl}^ healthy horses as react to this test 

 have to be slaughtered, compensation being paid to the owner. 



Two points in connection with the figures given in the 

 Table require some explanation. The first is that between 

 1904 and 1907 the outbreaks had fallen by nearly 50 per 

 cent, although the new Order did not come into force until 

 1908. This reduction can be accounted for by the fact that 

 prior to 1908 the very measures which can now be enforced 

 under the new Order were voluntarily employed hy many of 

 the large horse-owners in London, that is to say, many owners 

 had recognised that it would pay them to have the whole of 

 their horses tested at intervals with mallein with a view to 

 destroying or isolating those that reacted. 



The other point requiring explanation is that there has 

 been a greater fall in the number of outbreaks than in the 



