222 Journal op the Department of Agriculture. 



cause responsible for disease and death, was a toxin derived from 

 animal debris scattered about the veld. 



It may be recalled that an intoxication theory had been put 

 forward eight years ago by the senior author, l)ut that the toxin was 

 at that time associated witb the vegetation of tlic lamziekte areas 

 rather than \\\\\\ the animal deliris common to farms all over the 

 country. In the revised exposition tlie vegetation of tlie lamziekte areas 

 still plays a prominent role, but now becomes the renn)te and not i)n' 

 juimiiry cause. It accounts for a subsidiary complaint termed 

 " osteophagia," practically harmless in itself and not sufficiently 

 serious to deserve the name " disease," but of the utmost practical 

 consequence as an essential link in the etiological chain of lamziekte. 



Another old view of causation (the " pasteurella theory ") main- 

 tained that lamziekte was due to infection of the animal by a patho- 

 genic bacterium, and, although this had to be abandoned when 

 experimental investigation rendered it untenable, the new explana- 

 tion revived the idea of bacterial activity from an altogetlier diiferevt 

 angle of vision. Instead of a " pathogenic l)acterium " it jjredicated 

 a " toxicogenic -saprophyte " ; that is to say, an organism which lives 

 on dead organic matter but which does not infect the living animal, 

 or is harmless to the live animal until it has operated upon the 

 carcass of a dead one. 



Finally, the new view explained why it was that lamziekte was 

 mainly a disease of cattle, and although occasionally reported in the 

 goat and the ostrich, did not occur naturally amongst animals such 

 as the sheep and the horse. 



Indeed, nearly all the earlier theories on the causation of lam- 

 ziekte became involved in the new view, in the light of which they 

 all showed up as "partial truths." For this reason, perhaps, its 

 eiumciation was promptlv folloAved by a shoal of claimants foi the 

 honour of discovery. The novelty of the explanation offered in 

 March, 1919, was simplv that it seized upon the idea of a toxicogenic 

 saprophyte and forged together into one complete, chain all the loose 

 links of the past. As a coherent conception of causation it rendered 

 positive proof possible and opened a fresh field for experimental 

 inquiry into methods foi' control of the disease. 



The experimental work of the past year has abundantly justified 

 the earlier announcement, and much has been done towards 

 developing the original conception in directions of practical 

 conseqiience to the farmer. Methods for the prevention of lamziekte 

 are being worked out, and it is hoped that within the next few years 

 this dreaded disease will be lirought under control and the areas 

 decimated in the past once more liecome profitable for cattle 

 rearing. 



The purpose of this article is to give a })Opular account of the 

 facts so far ascertained and of the lines of attack now being followed 

 up, the detailed exposition of the experimental protocols being 

 reserved for a more technical publication. Figures, wearisome to 

 the general reader, will be avoided as far as possible and only a 

 running commentary offered. 



The Chain of CArsATioN. 



The conception itself was communicated in a Press interview for 

 the Farmers' Weekly of 7th May last year, but may be recapitulated 



