22 Mol)E3 OF- Infection. 



the retention of the virus there. To see whether or no 

 the virus in our case persists for a long time, as in Texas 

 fever, five healthy horses were kept over a month in 

 the autumn of 1909 in the Higashima pasture belong- 

 ing to Hagino Branch of the Remount Depot of the 

 Military Horses, where many patients had been produced 

 year after year until 1908. The result was negative. 

 But from this we cannot deny the presence of the virus 

 in the field ; this negative result may be due to the ab- 

 sence of the transmitter of the disease ; for the experi- 

 ment was performed rather late in the season. To ex- 

 clude the above possibility the same experiment was 

 repeated in 1910 at the Masugata section of Izumi 

 pasture belonging to the Shirakawa Branch Remount 

 Dep6t, where patients had been exceptionally abundant 

 in 1909. Should the virus, winter in some form or 

 other, any healthy horses in the section would certainly 

 become affected. Six horses good in flesh and spirits 

 were pastured for 101 day in the summer (from July 5 

 to October 31), the usual season of prevalence of the 

 disease. All subjects kept up their health in spite of 

 the fact that during the experiment insects were thriving 

 and the horses were not well nourished owing to weak 

 growth of grass there. 



These experiments clearly show that the virus of 

 the disease is not retained for a long time in pasture 

 as is the germ of anthrax. Any pasture can, therefore, 

 be considered perfectly healthy, if the patients were 

 produced in the preceding years. 



2. It is a well known fact that infection of the 

 disease usually takes place in the pasture, but not in 

 the stable. However, to determine how dangerous the 

 patients or the virus-carriers are in the case of the 

 mixed pasturing, we must have recourse to pasturing 



