8() Tredtmetit of (jrass Land for Elimination of Disease. 



In the case of some of these organisms, residence in a 

 susceptil)le animal is not regarded as a condition essential to 

 life and increase. It is probable that under ordinary conditions 

 such soil-organisms rarely contaminate grass land in a highly 

 dangerous degree, but this may occur when carcasses of their 

 victims, which contain the germs of the disease, are allowed to 

 remain long on pastures or are otherwise improperly disposed 

 of. For example, it is well known that black quarter was 

 specially liable to occur among young cattle grazing in the 

 same situation year after year, sometimes causing serious loss, 

 and it was so lar recognised that there was little hope of 

 eliminating the risks of its occurrence by treatment of pastures 

 or of curing the affected that such supposed preventive measures 

 as setoning, rowelling, and inoculation were resorted to. While 

 we may possess no means for extirpating all such disease germs 

 from the soil, experience indicates that proper disposal of 

 diseased carcasses practically reduces to a minimum the risks 

 of I occurrence of diseases due to them, as during illness they 

 are not usually discharged on to the land. 



Anthrax, which includes amongst its subjects farm animals 

 of all species, is usually regarded as a disease often due to 

 contamination of pasture and very liable to recur on certain 

 grass lands. In countries in which the temperature is nor- 

 mally high for considerable portions of the year and other 

 conditions in the outer world favourable, the germs of this 

 disease may multiply, but under conditions ordinarily obtaining 

 in these islands, this probably but rarely occurs outside the 

 bodies of affected animals. Though during the late stages 

 of illness of the animal some anthrax bacilli may be dis- 

 charged, such discharge is usually not profuse, and as the 

 course of the disease is very short, grass land is not likely 

 to be widely contaminated by the living animal. Indeed, 

 the recurrence of anthrax in the same situation as a result of 

 contamination of pasture would, from the investigation of a 

 large number of so-called " outbreaks " by the Board of 

 Agriculture, appear to be far less common than was formerly 

 believed, while the fact that on the average less than two 

 animals die at each outbreak gives strong support to the same 

 view. There are, however, some situations in which anthrax 

 recurs periodically. Such may depend on the fact that if the 

 long rode-like anthrax organisms or liacilli in which form the 

 germs exist in the affected animal are exposed to the air they 

 produce spores, w^hich are capable under some circumstances of 

 retaining their vitality and efficiency in the outer world for 

 periods which may extend over years. Some grass lands are 

 also more open to the risks of fresh contamination as a result 

 of proximity to or connection with woollen, alpaca, or hide 



