Treatment of Grass Land for Elimination of Disease. 87 



factories, &c., while in the present day grazing animals are 

 believed to contract this malady from eating foreign-grown 

 artificial food, and from pastures treated with certain raw-bone 

 manures. In considering the treatment of grass land with the 

 view of elimination of anthrax the foregoing must be provided 

 for, but the recurrence of this disease on our pastures mainly 

 depends on improper disposal of carcasses and dejecta of its 

 victims, and if the conditions prescribed by law are observed, 

 there are few risks of pollution of pastures. As all kinds of 

 farm animals are susceptible to this disease it is not practical)le 

 to attempt its elimination by withdrawing those of any par- 

 ticular species, while ploughing might act deleteriously by 

 bringing buried spores to the surface. Its fatal nature and 

 communicability to man add a degree of seriousness to its 

 occurrence, but when it is realised that of nearly 40,000,000 

 grazing animals in this country the total annual number of 

 deaths attributed to anthrax is about 1,000, of which a con- 

 siderable proportion occur in stabled animals, it must be 

 concluded that it is not a common or widespread form of 

 contamination of pastures, and though under certain conditions 

 anthrax spores may retain their vitality for years, exposure 

 to the rays of the sun for a few hours kills them. 



Johne's Disease, an old acquaintance, which under a new 

 name looms somewhat largely in the public mind as a disease 

 affecting cattle, sheep, and some other ruminants, affords an 

 example of an affection in which large numbers of the causal 

 germs are discharged with the faeces of affected animals and 

 with which grass land may therefore become polluted. It also 

 occurs in stall-fed cattle, and manure made by them must be 

 regarded as infective. Though the micro-organisms giving 

 rise to this malady have retained their vitality for considerable 

 periods in the laboratory, little of a precise nature is known as 

 to how long they may remain dangerous on pasture, or of the 

 effect of the application of any material to its surface. The 

 means of eliminating the risks of contamination must be 

 sought for in preventing affected animals from depositing 

 the causal bacilli on our grass land. Animals become infected 

 by ingesting these micro-organisms, but the progress of the 

 disease is slow, and for a considerable period after the germs 

 have been taken in with food or water no distinctive symptoms 

 are shown, and with ordinary observation it is not possible to 

 diagnose its existence in the early stages when perhaps but 

 few germs are being passed. To avert contamination of grass 

 land it is desirable under all circumstances to remove affected 

 animals, isolate them, and to prevent manure made by them 

 from being spread on grass land. It would be of supreme 

 advantage to be able to discover the infected animal before the 



