8-4 Treatment of Grass hand for Kliinination of Disease. 



lies in the fact thar tlie older anijiials contaminate pastures by 

 the deposition of ova or emljrjos of worms Avhich naturally 

 inhabit their internal organs. 



It has to be admitted that in the majority of cases, when 

 our live stock are so heavily infested with parasitic woi*ms as 

 to show definite symptoms of disease, remedial measures are 

 not usually effectual. Experiments in the laboratory as to the 

 effect of medicines in general use for the death or expulsion of 

 worms do not favour the view that they are easily killed 

 by these agents at a strength compatible with the health 

 and life of animals in which worms exist. It would appear 

 that before the existence of the disease is manifested l)y 

 distinctive symptoms, the damage done is often beyond any 

 repair we can fairh' expect from the use of drugs, whose action 

 is now known to us. It is within the range of possibility that 

 in case of apparently healthy animals harbouring a few parasites 

 the administration of certain medicines may render conditions 

 within the animals uncongenial to worms and effect their 

 expulsion ; and in situations in which it is known that worm 

 disease is liable to prevail it may be advisable to administer 

 some worm medicine to animals in the spring and early 

 summer, after doing so placing them on land which is to be 

 ploughed. The use of rock-salt, and salt mixed with trough 

 food is possibly beneficial. 



Mucli has been written and said as to the benefits likely to 

 accrue from the application of agents such as lime, salt, soot, 

 &c., to contaminated grass land with the object of purifying it 

 from disease, while it is claimed by some commercially 

 interested in artificial manures that some of these are effective. 

 Laboratory experiences do not indicate that lime, salt, or soot 

 applied in such amounts as are compatible with the life and 

 well doing of herbage and live stock are likely to desti'oy all 

 the disease-producing agents polluting grass land, but as 

 instanced in case of the effect of salt on the fresh- water snail, 

 which entertains the immature fluke, it is, perhaps, possible 

 that either or all of the materials named may provide circum- 

 stances unfavourable to parasites in some phase of their 

 development. The effect of lime on soil, we know, is 

 sometimes remarkable. Our knowledge of its deleterious effect 

 on soil bacteria is far from complete, but it has been seriously 

 suggested very recently that it is capal^le of effecting some 

 measure of soil-sterilisation. "While the addition of lime to 

 many soils is so often followed by growth of superior herbage, 

 its application to " tainted " pasture may be advisable, though 

 in our present state of knowledge we cannot suggest that it 

 should take the place of other measures named, but used in 

 conjunction with them at the rate of 2 or 3 ton of slaked lime 



