Treatment of Grass Laud for Elhiii nation oj Disease. 75 



products of the soil or that the cause is inherent to the 

 situation. While, however, the stigma of being unhealthy or 

 unsound may have rightly been attached to some pastures for 

 generations, many instances could be cited in which the 

 disease has ceased to appear in animals grazing in such 

 situations, and there is ample evidence showing that some 

 situations, which have for equal periods enjoyed a high 

 character for freedom from disease of stock, have acquired 

 an ^^nenviable reputation in consequence of the appearance 

 and recurrence of disease in animals grazing on them. There 

 would appear to. be a general impression that disease is more 

 common in animals on old permanent than on new or 

 temporary pastures, but we know that serious fatalities may 

 and do occur on the latter. There is, however, reason for 

 supposing that one of the consequences of extending the life of 

 pasture may be increased liability of stock grazing on it to 

 contract disease. Rich soil, which is the basis of rich pasture, 

 and the ground on which much of it has become permanent, 

 supplies, at any rate, one of the conditions favourable to, 

 though not necessarily determining, the occurrence of disease, 

 inasmuch as its plentiful supply of herbage admits of keeping 

 large numbers of animals in relatively small areas, and so of 

 increasing the risk of contamination. Low-lying, as compared 

 with upland, pastures are often regarded as prone to disease 

 partly for the last named reason, but mainly because conditions 

 often obtaining in such situations are more congenial to the 

 life and development of some disease-producing agents and so 

 to recurrence of disease in serious form. It is highly important 

 to recognise that the incidence and effect of disease on grazing 

 animals mux be materially influenced by situation and soil, but 

 disease is limited to no kind of pasture, and is not a product 

 of the soil or herbage in any other sense than cattle or sheep 

 are. It is, of course, realised that the quality of pasture 

 depends on the nature of the soil, situation, and the treatment 

 applied to it, and that the highest degree of health in con- 

 junction with rapid progress is favoured by feeding on herbage 

 composed of plants known from experience to be best adapted 

 to the I'equirements of animals of various species. Diseases 

 to which attention will be directed are set up by living 

 organisms, and, important as the foregoing circumstance may 

 be, for our purpose it must be insisted on that they cannot 

 be regarded as the cause of disease farther than they may 

 provide conditions favoura])le to the contamination of grass 

 land and animals with the living organisms severally capable 

 of inducing the respective diseases. It is not proposed to 

 refer to those disorders of live stock, which may result from 

 the ingestion of herbage rendered harmful by inclusion of 



